CVE-2026-32792

NLnet Labs Unbound 1.6.2 up to and including version 1.25.0 has a denial of service vulnerability when compiled with DNSCrypt support ('--enable-dnscrypt'). A bad DNSCrypt query could underflow Unbound's DNSCrypt packet reading procedure that may lead to heap overflow. A malicious actor can exploit the vulnerability with a single bad DNSCrypt query that its decrypted plaintext consists entirely of '0x00' bytes and does not contain the expected '0x80' marker. Unbound would then start reading more bytes than necessary until it finds a non-'0x00' byte. Based on the underlying memory allocator and the memory layout, it could lead to heap overflow while reading followed by a crash. Likelihood of a crash is low, since it relies heavily on the underlying memory allocator and the memory layout. If the heap overflow does not happen, Unbound's later packet checks will deny the packet. Unbound 1.25.1 contains a patch with a fix to bound reading in the given buffer space.

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 1.6.2 up to and including version 1.25.0 has a denial of service vulnerability when compiled with DNSCrypt support ('--enable-dnscrypt'). A bad DNSCrypt query could underflow Unbound's DNSCrypt packet reading procedure that may lead to heap overflow. A malicious actor can exploit the vulnerability with a single bad DNSCrypt query that its decrypted plaintext consists entirely of '0x00' bytes and does not contain the expected '0x80' marker. Unbound would then start reading more bytes than necessary until it finds a non-'0x00' byte. Based on the underlying memory allocator and the memory layout, it could lead to heap overflow while reading followed by a crash. Likelihood of a crash is low, since it relies heavily on the underlying memory allocator and the memory layout. If the heap overflow does not happen, Unbound's later packet checks will deny the packet. Unbound 1.25.1 contains a patch with a fix to bound reading in the given buffer space.(CVE-2026-32792)

NLnet Labs Unbound 1.16.2 up to and including version 1.25.0 has a vulnerability of the 'ghost domain names' family of attacks that could extend the ghost domain window by up to one cached TTL configured value. Similar to other 'ghost domain names' attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single client NS query can cause Unbound to overwrite the cached expired parent-side referral NS rrset with the child-side apex NS rrset and essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In configurations where 'harden-referral-path: yes' is used (non-default configuration), no client NS query is required since Unbound implicitly performs that query. Unbound 1.25.1 contains a patch with a fix that does not allow extension of TTLs for (parent) NS records regardless of their trust.(CVE-2026-40622)

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the jostle logic that could defeat its purpose and degrade resolution performance. Retransmits of the same query could renew the age of slow running queries and not allow the jostle logic to see them as aged and potential targets for replacement with new queries. An adversary who can query a vulnerable Unbound and who can control a domain name server that replies slowly and/or maliciously to Unbound's queries can exploit the vulnerability and degrade the resolution performance of Unbound. When Unbound's 'num-queries-per-thread' reaches its limit, the jostle logic kicks in. When a new query comes in, half of the available queries that are also slow to resolve are candidates for replacement. The vulnerability then happens because duplicate queries that need resolution would skew the aging result by using the timestamp of the latest duplicate query instead of the original one that started the resolution effort. Cache and local data response performance remains unaffected. Coordinated attacks could raise this to a denial of resolution service. Unbound 1.25.1 contains a patch with a fix to attach an initial, non-updatable start time for incoming queries that allow the jostle logic to work as intended.(CVE-2026-42534)

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the DNSSEC validator where the code…

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 1.6.2 up to and including version 1.25.0 has a denial of service vulnerability when compiled with DNSCrypt support ('--enable-dnscrypt'). A bad DNSCrypt query could underflow Unbound's DNSCrypt packet reading procedure that may lead to heap overflow. A malicious actor can exploit the vulnerability with a single bad DNSCrypt query that its decrypted plaintext consists entirely of '0x00' bytes and does not contain the expected '0x80' marker. Unbound would then start reading more bytes than necessary until it finds a non-'0x00' byte. Based on the underlying memory allocator and the memory layout, it could lead to heap overflow while reading followed by a crash. Likelihood of a crash is low, since it relies heavily on the underlying memory allocator and the memory layout. If the heap overflow does not happen, Unbound's later packet checks will deny the packet. Unbound 1.25.1 contains a patch with a fix to bound reading in the given buffer space.(CVE-2026-32792)

NLnet Labs Unbound 1.16.2 up to and including version 1.25.0 has a vulnerability of the 'ghost domain names' family of attacks that could extend the ghost domain window by up to one cached TTL configured value. Similar to other 'ghost domain names' attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single client NS query can cause Unbound to overwrite the cached expired parent-side referral NS rrset with the child-side apex NS rrset and essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In configurations where 'harden-referral-path: yes' is used (non-default configuration), no client NS query is required since Unbound implicitly performs that query. Unbound 1.25.1 contains a patch with a fix that does not allow extension of TTLs for (parent) NS records regardless of their trust.(CVE-2026-40622)

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the jostle logic that could defeat its purpose and degrade resolution performance. Retransmits of the same query could renew the age of slow running queries and not allow the jostle logic to see them as aged and potential targets for replacement with new queries. An adversary who can query a vulnerable Unbound and who can control a domain name server that replies slowly and/or maliciously to Unbound's queries can exploit the vulnerability and degrade the resolution performance of Unbound. When Unbound's 'num-queries-per-thread' reaches its limit, the jostle logic kicks in. When a new query comes in, half of the available queries that are also slow to resolve are candidates for replacement. The vulnerability then happens because duplicate queries that need resolution would skew the aging result by using the timestamp of the latest duplicate query instead of the original one that started the resolution effort. Cache and local data response performance remains unaffected. Coordinated attacks could raise this to a denial of resolution service. Unbound 1.25.1 contains a patch with a fix to attach an initial, non-updatable start time for incoming queries that allow the jostle logic to work as intended.(CVE-2026-42534)

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the DNSSEC validator where the code…

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 1.6.2 up to and including version 1.25.0 has a denial of service vulnerability when compiled with DNSCrypt support ('--enable-dnscrypt'). A bad DNSCrypt query could underflow Unbound's DNSCrypt packet reading procedure that may lead to heap overflow. A malicious actor can exploit the vulnerability with a single bad DNSCrypt query that its decrypted plaintext consists entirely of '0x00' bytes and does not contain the expected '0x80' marker. Unbound would then start reading more bytes than necessary until it finds a non-'0x00' byte. Based on the underlying memory allocator and the memory layout, it could lead to heap overflow while reading followed by a crash. Likelihood of a crash is low, since it relies heavily on the underlying memory allocator and the memory layout. If the heap overflow does not happen, Unbound's later packet checks will deny the packet. Unbound 1.25.1 contains a patch with a fix to bound reading in the given buffer space.(CVE-2026-32792)

NLnet Labs Unbound 1.16.2 up to and including version 1.25.0 has a vulnerability of the 'ghost domain names' family of attacks that could extend the ghost domain window by up to one cached TTL configured value. Similar to other 'ghost domain names' attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single client NS query can cause Unbound to overwrite the cached expired parent-side referral NS rrset with the child-side apex NS rrset and essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In configurations where 'harden-referral-path: yes' is used (non-default configuration), no client NS query is required since Unbound implicitly performs that query. Unbound 1.25.1 contains a patch with a fix that does not allow extension of TTLs for (parent) NS records regardless of their trust.(CVE-2026-40622)

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the jostle logic that could defeat its purpose and degrade resolution performance. Retransmits of the same query could renew the age of slow running queries and not allow the jostle logic to see them as aged and potential targets for replacement with new queries. An adversary who can query a vulnerable Unbound and who can control a domain name server that replies slowly and/or maliciously to Unbound's queries can exploit the vulnerability and degrade the resolution performance of Unbound. When Unbound's 'num-queries-per-thread' reaches its limit, the jostle logic kicks in. When a new query comes in, half of the available queries that are also slow to resolve are candidates for replacement. The vulnerability then happens because duplicate queries that need resolution would skew the aging result by using the timestamp of the latest duplicate query instead of the original one that started the resolution effort. Cache and local data response performance remains unaffected. Coordinated attacks could raise this to a denial of resolution service. Unbound 1.25.1 contains a patch with a fix to attach an initial, non-updatable start time for incoming queries that allow the jostle logic to work as intended.(CVE-2026-42534)

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the DNSSEC validator where the code…

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 1.6.2 up to and including version 1.25.0 has a denial of service vulnerability when compiled with DNSCrypt support ('--enable-dnscrypt'). A bad DNSCrypt query could underflow Unbound's DNSCrypt packet reading procedure that may lead to heap overflow. A malicious actor can exploit the vulnerability with a single bad DNSCrypt query that its decrypted plaintext consists entirely of '0x00' bytes and does not contain the expected '0x80' marker. Unbound would then start reading more bytes than necessary until it finds a non-'0x00' byte. Based on the underlying memory allocator and the memory layout, it could lead to heap overflow while reading followed by a crash. Likelihood of a crash is low, since it relies heavily on the underlying memory allocator and the memory layout. If the heap overflow does not happen, Unbound's later packet checks will deny the packet. Unbound 1.25.1 contains a patch with a fix to bound reading in the given buffer space.(CVE-2026-32792)

NLnet Labs Unbound 1.16.2 up to and including version 1.25.0 has a vulnerability of the 'ghost domain names' family of attacks that could extend the ghost domain window by up to one cached TTL configured value. Similar to other 'ghost domain names' attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single client NS query can cause Unbound to overwrite the cached expired parent-side referral NS rrset with the child-side apex NS rrset and essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In configurations where 'harden-referral-path: yes' is used (non-default configuration), no client NS query is required since Unbound implicitly performs that query. Unbound 1.25.1 contains a patch with a fix that does not allow extension of TTLs for (parent) NS records regardless of their trust.(CVE-2026-40622)

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the jostle logic that could defeat its purpose and degrade resolution performance. Retransmits of the same query could renew the age of slow running queries and not allow the jostle logic to see them as aged and potential targets for replacement with new queries. An adversary who can query a vulnerable Unbound and who can control a domain name server that replies slowly and/or maliciously to Unbound's queries can exploit the vulnerability and degrade the resolution performance of Unbound. When Unbound's 'num-queries-per-thread' reaches its limit, the jostle logic kicks in. When a new query comes in, half of the available queries that are also slow to resolve are candidates for replacement. The vulnerability then happens because duplicate queries that need resolution would skew the aging result by using the timestamp of the latest duplicate query instead of the original one that started the resolution effort. Cache and local data response performance remains unaffected. Coordinated attacks could raise this to a denial of resolution service. Unbound 1.25.1 contains a patch with a fix to attach an initial, non-updatable start time for incoming queries that allow the jostle logic to work as intended.(CVE-2026-42534)

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the DNSSEC validator where the code…

NLnet Labs Unbound 1.6.2 up to and including version 1.25.0 has a denial of service vulnerability when compiled with DNSCrypt support ('--enable-dnscrypt'). A bad DNSCrypt query could underflow Unbound's DNSCrypt packet reading procedure that may lead to heap overflow. A malicious actor can exploit the vulnerability with a single bad DNSCrypt query that its decrypted plaintext consists entirely of '0x00' bytes and does not contain the expected '0x80' marker. Unbound would then start reading more bytes than necessary until it finds a non-'0x00' byte. Based on the underlying memory allocator and the memory layout, it could lead to heap overflow while reading followed by a crash. Likelihood of a crash is low, since it relies heavily on the underlying memory allocator and the memory layout. If the heap overflow does not happen, Unbound's later packet checks will deny the packet. Unbound 1.25.1 contains a patch with a fix to bound reading in the given buffer space.

NLnet Labs Unbound 1.6.2 up to and including version 1.25.0 has a denial of service vulnerability when compiled with DNSCrypt support ('--enable-dnscrypt'). A bad DNSCrypt query could underflow Unbound's DNSCrypt packet reading procedure that may lead to heap overflow. A malicious actor can exploit the vulnerability with a single bad DNSCrypt query that its decrypted plaintext consists entirely of '0x00' bytes and does not contain the expected '0x80' marker. Unbound would then start reading more bytes than necessary until it finds a non-'0x00' byte. Based on the underlying memory allocator and the memory layout, it could lead to heap overflow while reading followed by a crash. Likelihood of a crash is low, since it relies heavily on the underlying memory allocator and the memory layout. If the heap overflow does not happen, Unbound's later packet checks will deny the packet. Unbound 1.25.1 contains a patch with a fix to bound reading in the given buffer space.

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).

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)