CVE-2026-41292

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).

Unbound is a validating, recursive, caching DNS resolver. It is designed to be fast and lean and incorporates modern features based on open standards. To help increase online privacy, Unbound supports DNS-over-TLS which allows clients to encrypt their communication. Unbound is available for most platforms such as FreeBSD, OpenBSD, NetBSD, MacOS, Linux and Microsoft Windows. Unbound is a totally free, open source software under the BSD license. It doesn't make custom builds or provide specific features to paying customers only.

Security Fix(es):

NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.(CVE-2026-33278)

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).(CVE-2026-41292)

NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation.(CVE-2026-42944)

NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong counter to calculate write offsets for ADDITIONAL section rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator later dereferences this uninitialized pointer, causing an immediate process crash. An adversary controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write offsets.(CVE-2026-42959)

NLnet Labs Unbound up to and including…

Unbound is a validating, recursive, caching DNS resolver. It is designed to be fast and lean and incorporates modern features based on open standards. To help increase online privacy, Unbound supports DNS-over-TLS which allows clients to encrypt their communication. Unbound is available for most platforms such as FreeBSD, OpenBSD, NetBSD, MacOS, Linux and Microsoft Windows. Unbound is a totally free, open source software under the BSD license. It doesn't make custom builds or provide specific features to paying customers only.

Security Fix(es):

NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.(CVE-2026-33278)

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).(CVE-2026-41292)

NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation.(CVE-2026-42944)

NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong counter to calculate write offsets for ADDITIONAL section rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator later dereferences this uninitialized pointer, causing an immediate process crash. An adversary controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write offsets.(CVE-2026-42959)

NLnet Labs Unbound up to and including…

Unbound is a validating, recursive, caching DNS resolver. It is designed to be fast and lean and incorporates modern features based on open standards. To help increase online privacy, Unbound supports DNS-over-TLS which allows clients to encrypt their communication. Unbound is available for most platforms such as FreeBSD, OpenBSD, NetBSD, MacOS, Linux and Microsoft Windows. Unbound is a totally free, open source software under the BSD license. It doesn't make custom builds or provide specific features to paying customers only.

Security Fix(es):

NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.(CVE-2026-33278)

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).(CVE-2026-41292)

NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong counter to calculate write offsets for ADDITIONAL section rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator later dereferences this uninitialized pointer, causing an immediate process crash. An adversary controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write offsets.(CVE-2026-42959)

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to poisoning via promiscuous records for the authority section. Promiscuous RRSets that complement DNS replies in the authority section can be used to trick Unbound to cache such records. If an adversary is able to attach such records in a reply (i.e., spoofed packet, fragmentation attack) he would be able to poison Unbound's cache. A malicious actor can exploit the possible poisonous effect by injecting RRSets other than NS that are also accompanied by address records in a reply, for example MX. This could be achieved by trying to spoof a reply packet or fragmentation attacks. Unbound would then accept the relative address records in the additional section and cache them if the authority RRSet has enough trust at this point, i.e., in-zone data for the delegation point. Unbound 1.25.1 contains a patch with a fix that disregards address records from the additional section if they are not…

Unbound is a validating, recursive, caching DNS resolver. It is designed to be fast and lean and incorporates modern features based on open standards. To help increase online privacy, Unbound supports DNS-over-TLS which allows clients to encrypt their communication. Unbound is available for most platforms such as FreeBSD, OpenBSD, NetBSD, MacOS, Linux and Microsoft Windows. Unbound is a totally free, open source software under the BSD license. It doesn't make custom builds or provide specific features to paying customers only.

Security Fix(es):

NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.(CVE-2026-33278)

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).(CVE-2026-41292)

NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong counter to calculate write offsets for ADDITIONAL section rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator later dereferences this uninitialized pointer, causing an immediate process crash. An adversary controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write offsets.(CVE-2026-42959)

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to poisoning via promiscuous records for the authority section. Promiscuous RRSets that complement DNS replies in the authority section can be used to trick Unbound to cache such records. If an adversary is able to attach such records in a reply (i.e., spoofed packet, fragmentation attack) he would be able to poison Unbound's cache. A malicious actor can exploit the possible poisonous effect by injecting RRSets other than NS that are also accompanied by address records in a reply, for example MX. This could be achieved by trying to spoof a reply packet or fragmentation attacks. Unbound would then accept the relative address records in the additional section and cache them if the authority RRSet has enough trust at this point, i.e., in-zone data for the delegation point. Unbound 1.25.1 contains a patch with a fix that disregards address records from the additional section if they are not…

Unbound is a validating, recursive, caching DNS resolver. It is designed to be fast and lean and incorporates modern features based on open standards. To help increase online privacy, Unbound supports DNS-over-TLS which allows clients to encrypt their communication. Unbound is available for most platforms such as FreeBSD, OpenBSD, NetBSD, MacOS, Linux and Microsoft Windows. Unbound is a totally free, open source software under the BSD license. It doesn't make custom builds or provide specific features to paying customers only.

Security Fix(es):

NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.(CVE-2026-33278)

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).(CVE-2026-41292)

NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation.(CVE-2026-42944)

NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong counter to calculate write offsets for ADDITIONAL section rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator later dereferences this uninitialized pointer, causing an immediate process crash. An adversary controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write offsets.(CVE-2026-42959)

NLnet Labs Unbound up to and including…

The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver.

Security Fix(es):

• unbound: Unbound: Denial of Service via excessive EDNS options (CVE-2026-41292)

• unbound: Unbound: Cache manipulation via 'ghost domain names' attack (CVE-2026-40622)

• unbound: Unbound: Denial of Service due to excessive resource consumption with large DNS Resource Record Sets (CVE-2026-44390)

• unbound: Unbound: Denial of Service due to degraded resolution performance in jostle logic (CVE-2026-42534)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver.

Security Fix(es):

• unbound: Unbound: Denial of Service via excessive EDNS options (CVE-2026-41292)

• unbound: Unbound: Cache manipulation via 'ghost domain names' attack (CVE-2026-40622)

• unbound: Unbound: Denial of Service due to excessive resource consumption with large DNS Resource Record Sets (CVE-2026-44390)

• unbound: Unbound: Denial of Service due to degraded resolution performance in jostle logic (CVE-2026-42534)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver.

Security Fix(es):

• unbound: Unbound: Denial of Service via excessive EDNS options (CVE-2026-41292)

• unbound: Unbound: Cache manipulation via 'ghost domain names' attack (CVE-2026-40622)

• unbound: Unbound: Denial of Service due to excessive resource consumption with large DNS Resource Record Sets (CVE-2026-44390)

• unbound: Unbound: Denial of Service due to degraded resolution performance in jostle logic (CVE-2026-42534)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Root has patched CVE-2026-41292 in the unbound package for Root:Debian:11. Multiple fixed versions available.

Root has patched CVE-2026-41292 in the unbound package for Root:Debian:12. Multiple fixed versions available.

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).

The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver.

Security Fix(es):

• unbound: Unbound: Denial of Service via excessive EDNS options (CVE-2026-41292)
• unbound: Unbound: Cache manipulation via 'ghost domain names' attack (CVE-2026-40622)
• unbound: Unbound: Denial of Service due to excessive resource consumption with large DNS Resource Record Sets (CVE-2026-44390)
• unbound: Unbound: Denial of Service due to degraded resolution performance in jostle logic (CVE-2026-42534)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver.

Security Fix(es):

• unbound: Unbound: Denial of Service via excessive EDNS options (CVE-2026-41292)
• unbound: Unbound: Cache manipulation via 'ghost domain names' attack (CVE-2026-40622)
• unbound: Unbound: Denial of Service due to excessive resource consumption with large DNS Resource Record Sets (CVE-2026-44390)
• unbound: Unbound: Denial of Service due to degraded resolution performance in jostle logic (CVE-2026-42534)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver.

Security Fix(es):

• unbound: Unbound: Denial of Service via excessive EDNS options (CVE-2026-41292)
• unbound: Unbound: Cache manipulation via 'ghost domain names' attack (CVE-2026-40622)
• unbound: Unbound: Denial of Service due to excessive resource consumption with large DNS Resource Record Sets (CVE-2026-44390)
• unbound: Unbound: Denial of Service due to degraded resolution performance in jostle logic (CVE-2026-42534)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).

• CVE-2026-42960: fix cache poisoning while following delegation
• CVE-2026-42959: fix crash during DNSSEC validation of malicious content
• CVE-2026-41292: limit incoming EDNS options to prevent DoS

• CVE-2026-42960: fix cache poisoning while following delegation
• CVE-2026-42959: fix crash during DNSSEC validation of malicious content
• CVE-2026-41292: limit incoming EDNS options to prevent DoS

• CVE-2026-42960: fix cache poisoning while following delegation
• CVE-2026-42959: fix crash during DNSSEC validation of malicious content
• CVE-2026-41292: limit incoming EDNS options to prevent DoS

• CVE-2026-42944: fix heap overflow when a query contains multiple NSID or PADDING EDNS options; only emit each option once per query via nsid_seen / padding_seen guards (COOKIE handler does not exist in 1.16.2)
• CVE-2026-41292: cap parsed incoming EDNS options at 100 per query so a flood of options cannot hold a resolver worker thread
• CVE-2026-42959: fix DNSSEC-validation crash in val_fill_reply() by using chase->ns_numrrsets instead of the wrong orig->ns_numrrsets when computing the chase rrsets offset

• CVE-2026-41292: cap parsed incoming EDNS options at 100 to prevent per-thread parse stalls under crafted long-option-list queries
• CVE-2026-42944: de-duplicate NSID/Padding EDNS options at parse time to prevent heap overflow during EDNS encoding in attach_edns_record
• CVE-2026-44608: hold the auth-zone read lock across nsip/nsdname trigger application in rpz_callback_from_iterator_module to avoid use-after-free under concurrent RPZ XFR reload

• CVE-2026-42960: prevent cache poisoning via promiscuous additional-section records by marking glue only for NS RRsets in the authority section [ELSCVE-130594]
• CVE-2026-42944: fix heap overflow and crash with multiple NSID and PADDING EDNS options by deduplicating options and adding bounds checks in attach_edns_record_max_msg_sz [ELSCVE-130649]
• CVE-2026-41292: cap parsed EDNS options at MAX_PARSED_EDNS_OPTIONS (100) to prevent DoS via long option lists [ELSCVE-130636]
• CVE-2026-42959: fix out-of-bounds write in val_fill_reply by indexing the destination array with chase->ns_numrrsets instead of orig->ns_numrrsets [ELSCVE-130615]
• CVE-2026-40622: prevent ghost-domain TTL extension by clamping newd->ttl to cached->ttl in the higher-trust branch of need_to_update_rrset [ELSCVE-129354]

These are all security issues fixed in the libunbound8-1.25.1-1.1 package on the GA media of openSUSE Tumbleweed.

This update for unbound fixes the following issues

• CVE-2026-32792: Packet of death with DNSCrypt (bsc#1265583).
• CVE-2026-33278: Possible remote code execution during DNSSEC validation (bsc#1265587).
• CVE-2026-40622: "Ghost domain name" variant (bsc#1265581).
• CVE-2026-41292: Parsing a long list of incoming EDNS options degrades performance (bsc#1265580).
• CVE-2026-42534: Jostle logic bypass degrades resolution performance (bsc#1265585).
• CVE-2026-42923: Degradation of service with unbounded NSEC3 hash calculations (bsc#1265589).
• CVE-2026-42944: Heap overflow and crash with multiple nsid, cookie, padding EDNS options (bsc#1265578).
• CVE-2026-42959: Crash during DNSSEC validation of malicious content (bsc#1265586).
• CVE-2026-42960: Possible cache poisoning attack while following delegation (bsc#1265588).
• CVE-2026-44390: Unbounded name compression in certain cases causes degradation of service (bsc#1265584).
• CVE-2026-44608: Use after free and crash in RPZ code (bsc#1265582).

This update for unbound fixes the following issues

• CVE-2026-32792: Packet of death with DNSCrypt (bsc#1265583).
• CVE-2026-33278: Possible remote code execution during DNSSEC validation (bsc#1265587).
• CVE-2026-40622: "Ghost domain name" variant (bsc#1265581).
• CVE-2026-41292: Parsing a long list of incoming EDNS options degrades performance (bsc#1265580).
• CVE-2026-42534: Jostle logic bypass degrades resolution performance (bsc#1265585).
• CVE-2026-42923: Degradation of service with unbounded NSEC3 hash calculations (bsc#1265589).
• CVE-2026-42944: Heap overflow and crash with multiple nsid, cookie, padding EDNS options (bsc#1265578).
• CVE-2026-42959: Crash during DNSSEC validation of malicious content (bsc#1265586).
• CVE-2026-42960: Possible cache poisoning attack while following delegation (bsc#1265588).
• CVE-2026-44390: Unbounded name compression in certain cases causes degradation of service (bsc#1265584).
• CVE-2026-44608: Use after free and crash in RPZ code (bsc#1265582).

This update for unbound fixes the following issues

• CVE-2026-32792: Packet of death with DNSCrypt (bsc#1265583).
• CVE-2026-33278: Possible remote code execution during DNSSEC validation (bsc#1265587).
• CVE-2026-40622: "Ghost domain name" variant (bsc#1265581).
• CVE-2026-41292: Parsing a long list of incoming EDNS options degrades performance (bsc#1265580).
• CVE-2026-42534: Jostle logic bypass degrades resolution performance (bsc#1265585).
• CVE-2026-42923: Degradation of service with unbounded NSEC3 hash calculations (bsc#1265589).
• CVE-2026-42944: Heap overflow and crash with multiple nsid, cookie, padding EDNS options (bsc#1265578).
• CVE-2026-42959: Crash during DNSSEC validation of malicious content (bsc#1265586).
• CVE-2026-42960: Possible cache poisoning attack while following delegation (bsc#1265588).
• CVE-2026-44390: Unbounded name compression in certain cases causes degradation of service (bsc#1265584).
• CVE-2026-44608: Use after free and crash in RPZ code (bsc#1265582).

This update for unbound fixes the following issues

• CVE-2026-32792: Packet of death with DNSCrypt (bsc#1265583).
• CVE-2026-33278: Possible remote code execution during DNSSEC validation (bsc#1265587).
• CVE-2026-40622: "Ghost domain name" variant (bsc#1265581).
• CVE-2026-41292: Parsing a long list of incoming EDNS options degrades performance (bsc#1265580).
• CVE-2026-42534: Jostle logic bypass degrades resolution performance (bsc#1265585).
• CVE-2026-42923: Degradation of service with unbounded NSEC3 hash calculations (bsc#1265589).
• CVE-2026-42944: Heap overflow and crash with multiple nsid, cookie, padding EDNS options (bsc#1265578).
• CVE-2026-42959: Crash during DNSSEC validation of malicious content (bsc#1265586).
• CVE-2026-42960: Possible cache poisoning attack while following delegation (bsc#1265588).
• CVE-2026-44390: Unbounded name compression in certain cases causes degradation of service (bsc#1265584).
• CVE-2026-44608: Use after free and crash in RPZ code (bsc#1265582).

This update for unbound fixes the following issues

• CVE-2026-32792: Packet of death with DNSCrypt (bsc#1265583).
• CVE-2026-33278: Possible remote code execution during DNSSEC validation (bsc#1265587).
• CVE-2026-40622: "Ghost domain name" variant (bsc#1265581).
• CVE-2026-41292: Parsing a long list of incoming EDNS options degrades performance (bsc#1265580).
• CVE-2026-42534: Jostle logic bypass degrades resolution performance (bsc#1265585).
• CVE-2026-42923: Degradation of service with unbounded NSEC3 hash calculations (bsc#1265589).
• CVE-2026-42944: Heap overflow and crash with multiple nsid, cookie, padding EDNS options (bsc#1265578).
• CVE-2026-42959: Crash during DNSSEC validation of malicious content (bsc#1265586).
• CVE-2026-42960: Possible cache poisoning attack while following delegation (bsc#1265588).
• CVE-2026-44390: Unbounded name compression in certain cases causes degradation of service (bsc#1265584).
• CVE-2026-44608: Use after free and crash in RPZ code (bsc#1265582).

This update for unbound fixes the following issues

• CVE-2026-32792: Packet of death with DNSCrypt (bsc#1265583).
• CVE-2026-33278: Possible remote code execution during DNSSEC validation (bsc#1265587).
• CVE-2026-40622: 'Ghost domain name' variant (bsc#1265581).
• CVE-2026-41292: Parsing a long list of incoming EDNS options degrades performance (bsc#1265580).
• CVE-2026-42534: Jostle logic bypass degrades resolution performance (bsc#1265585).
• CVE-2026-42923: Degradation of service with unbounded NSEC3 hash calculations (bsc#1265589).
• CVE-2026-42944: Heap overflow and crash with multiple nsid, cookie, padding EDNS options (bsc#1265578).
• CVE-2026-42959: Crash during DNSSEC validation of malicious content (bsc#1265586).
• CVE-2026-42960: Possible cache poisoning attack while following delegation (bsc#1265588).
• CVE-2026-44390: Unbounded name compression in certain cases causes degradation of service (bsc#1265584).
• CVE-2026-44608: Use after free and crash in RPZ code (bsc#1265582).

This update for unbound fixes the following issues

• CVE-2026-32792: Packet of death with DNSCrypt (bsc#1265583).
• CVE-2026-33278: Possible remote code execution during DNSSEC validation (bsc#1265587).
• CVE-2026-40622: 'Ghost domain name' variant (bsc#1265581).
• CVE-2026-41292: Parsing a long list of incoming EDNS options degrades performance (bsc#1265580).
• CVE-2026-42534: Jostle logic bypass degrades resolution performance (bsc#1265585).
• CVE-2026-42923: Degradation of service with unbounded NSEC3 hash calculations (bsc#1265589).
• CVE-2026-42944: Heap overflow and crash with multiple nsid, cookie, padding EDNS options (bsc#1265578).
• CVE-2026-42959: Crash during DNSSEC validation of malicious content (bsc#1265586).
• CVE-2026-42960: Possible cache poisoning attack while following delegation (bsc#1265588).
• CVE-2026-44390: Unbounded name compression in certain cases causes degradation of service (bsc#1265584).
• CVE-2026-44608: Use after free and crash in RPZ code (bsc#1265582).

USN-8282-1 fixed vulnerabilities in Unbound. This update provides the corresponding updates for CVE-2026-41292 in Ubuntu 18.04 LTS and Ubuntu 20.04 LTS and CVE-2026-42959, CVE-2026-42960 in Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS.

Original advisory details:

Andrew Griffiths discovered that Unbound did not properly handle certain DNSCrypt packets. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service. (CVE-2026-32792)

Qifan Zhang discovered that Unbound incorrectly handled DNSSEC validation in certain situations. A remote attacker could possibly use this issue to execute arbitrary code. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-33278)

Qifan Zhang discovered that Unbound incorrectly handled certain ghost domain name records. A remote attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-40622)

Qifan Zhang discovered that Unbound did not properly limit processing of long EDNS option lists. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-41292)

Qifan Zhang discovered that Unbound incorrectly handled jostle logic under certain circumstances. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-42534)

Qifan Zhang discovered that Unbound did not properly bound NSEC3 hash calculations. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-42923)

Qifan Zhang discovered that Unbound incorrectly handled multiple EDNS options in certain situations. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-42944)

Qifan Zhang discovered that Unbound incorrectly handled DNSSEC validation of malicious content. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service. (CVE-2026-42959)

TaoFei Guo, Yang Luo, and JianJun Chen discovered that Unbound incorrectly handled delegation processing in certain situations. A remote attacker could possibly use this issue to poison the DNS cache and obtain sensitive information. (CVE-2026-42960)

Qifan Zhang discovered that Unbound did not properly bound name compression in certain cases. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-44390)

Qifan Zhang discovered that Unbound had a use-after-free issue in RPZ handling. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-44608)