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CVE-2020-8618

A buffer boundary check assertion in rdataset.c can fail incorrectly during zone transfer

4.9 MediumFix available

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
High
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

1.88%Up 0.6 points since Apr 14, 2021
90%50%10%1%

What each source reports

CVE List Score used 4.9

A buffer boundary check assertion in rdataset.c can fail incorrectly during zone transfer

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

Record
CVE-2020-8618
CVSS 3.1
4.9 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
EUVDEUVD-2020-29466 4.9

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

Record
EUVD-2020-29466
CVSS 3.1
4.9 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-03
GitHub AdvisoriesGHSA-2c3j-p34f-v2cr 4.9

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to...

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

Record
GHSA-2c3j-p34f-v2cr
CVSS 3.1
4.9 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-617
Updated
2026-11-02
NVD 4.9

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

Record
CVE-2020-8618
CVSS 3.1
4.9 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0
4.0 MediumAV:N/AC:L/Au:S/C:N/I:N/A:P
Weakness
CWE-617
Updated
2026-11-02
OSVALPINE-CVE-2020-8618 4.9

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

Record
ALPINE-CVE-2020-8618
CVSS 3.1
4.9 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVBELL-CVE-2020-8618 4.9

CVE-2020-8618 does not affect BellSoft software

Record
BELL-CVE-2020-8618
CVSS 3.1
4.9 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
Show 8 moreShow less
OSV 4.9

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

Record
CVE-2020-8618
CVSS 3.1
4.9 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2020-8618 4.9

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

Record
DEBIAN-CVE-2020-8618
CVSS 3.1
4.9 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2020-8618 4.9

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

Record
UBUNTU-CVE-2020-8618
CVSS 3.1
4.9 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVopenSUSE-SU-2020:1699-1 No score

Security update for bind

This update for bind fixes the following issues:

BIND was upgraded to version 9.16.6:

Note:

  • bind is now more strict in regards to DNSSEC. If queries are not working, check for DNSSEC issues. For instance, if bind is used in a namserver forwarder chain, the forwarding DNS servers must support DNSSEC.

Fixing security issues:

  • CVE-2020-8616: Further limit the number of queries that can be triggered from a request. Root and TLD servers are no longer exempt from max-recursion-queries. Fetches for missing name server. (bsc#1171740) Address records are limited to 4 for any domain.
  • CVE-2020-8617: Replaying a TSIG BADTIME response as a request could trigger an assertion failure. (bsc#1171740)
  • CVE-2019-6477: Fixed an issue where TCP-pipelined queries could bypass the tcp-clients limit (bsc#1157051).
  • CVE-2018-5741: Fixed the documentation (bsc#1109160).
  • CVE-2020-8618: It was possible to trigger an INSIST when determining whether a record would fit into a TCP message buffer (bsc#1172958).
  • CVE-2020-8619: It was possible to trigger an INSIST in lib/dns/rbtdb.c:new_reference() with a particular zone content and query patterns (bsc#1172958).
  • CVE-2020-8624: 'update-policy' rules of type 'subdomain' were incorrectly treated as 'zonesub' rules, which allowed keys used in 'subdomain' rules to update names outside of the specified subdomains. The problem was fixed by making sure 'subdomain' rules are again processed as described in the ARM (bsc#1175443).
  • CVE-2020-8623: When BIND 9 was compiled with native PKCS#11 support, it was possible to trigger an assertion failure in code determining the number of bits in the PKCS#11 RSA public key with a specially crafted packet (bsc#1175443).
  • CVE-2020-8621: named could crash in certain query resolution scenarios where QNAME minimization and forwarding were both enabled (bsc#1175443).
  • CVE-2020-8620: It was possible to trigger an assertion failure by sending a specially crafted large TCP DNS message (bsc#1175443).
  • CVE-2020-8622: It was possible to trigger an assertion failure when verifying the response to a TSIG-signed request (bsc#1175443).

Other issues fixed:

  • Add engine support to OpenSSL EdDSA implementation.
  • Add engine support to OpenSSL ECDSA implementation.
  • Update PKCS#11 EdDSA implementation to PKCS#11 v3.0.
  • Warn about AXFR streams with inconsistent message IDs.
  • Make ISC rwlock implementation the default again.
  • Fixed issues when using cookie-secrets for AES and SHA2 (bsc#1161168)
  • Installed the default files in /var/lib/named and created chroot environment on systems using transactional-updates (bsc#1100369, fate#325524)
  • Fixed an issue where bind was not working in FIPS mode (bsc#906079).
  • Fixed dependency issues (bsc#1118367 and bsc#1118368).
  • GeoIP support is now discontinued, now GeoIP2 is used(bsc#1156205).
  • Fixed an issue with FIPS (bsc#1128220).
  • The liblwres library is discontinued upstream and is no longer included.
  • Added service dependency on NTP to make sure the clock is accurate when bind is starts (bsc#1170667, bsc#1170713).
  • Reject DS records at the zone apex when loading master files. Log but otherwise ignore attempts to add DS records at the zone apex via UPDATE.
  • The default value of 'max-stale-ttl' has been changed from 1 week to 12 hours.
  • Zone timers are now exported via statistics channel.
  • The 'primary' and 'secondary' keywords, when used as parameters for 'check-names', were not processed correctly and were being ignored.
  • 'rndc dnstap -roll <value>' did not limit the number of saved files to <value>.
  • Add 'rndc dnssec -status' command.
  • Addressed a couple of situations where named could crash.
  • Changed /var/lib/named to owner root:named and perms rwxrwxr-t so that named, being a/the only member of the 'named' group has full r/w access yet cannot change directories owned by root in the case of a compromized named. [bsc#1173307, bind-chrootenv.conf]
  • Added…
Record
openSUSE-SU-2020:1699-1
Updated
2026-11-02
OSVopenSUSE-SU-2020:1701-1 No score

Security update for bind

This update for bind fixes the following issues:

BIND was upgraded to version 9.16.6:

Note:

  • bind is now more strict in regards to DNSSEC. If queries are not working, check for DNSSEC issues. For instance, if bind is used in a namserver forwarder chain, the forwarding DNS servers must support DNSSEC.

Fixing security issues:

  • CVE-2020-8616: Further limit the number of queries that can be triggered from a request. Root and TLD servers are no longer exempt from max-recursion-queries. Fetches for missing name server. (bsc#1171740) Address records are limited to 4 for any domain.
  • CVE-2020-8617: Replaying a TSIG BADTIME response as a request could trigger an assertion failure. (bsc#1171740)
  • CVE-2019-6477: Fixed an issue where TCP-pipelined queries could bypass the tcp-clients limit (bsc#1157051).
  • CVE-2018-5741: Fixed the documentation (bsc#1109160).
  • CVE-2020-8618: It was possible to trigger an INSIST when determining whether a record would fit into a TCP message buffer (bsc#1172958).
  • CVE-2020-8619: It was possible to trigger an INSIST in lib/dns/rbtdb.c:new_reference() with a particular zone content and query patterns (bsc#1172958).
  • CVE-2020-8624: 'update-policy' rules of type 'subdomain' were incorrectly treated as 'zonesub' rules, which allowed keys used in 'subdomain' rules to update names outside of the specified subdomains. The problem was fixed by making sure 'subdomain' rules are again processed as described in the ARM (bsc#1175443).
  • CVE-2020-8623: When BIND 9 was compiled with native PKCS#11 support, it was possible to trigger an assertion failure in code determining the number of bits in the PKCS#11 RSA public key with a specially crafted packet (bsc#1175443).
  • CVE-2020-8621: named could crash in certain query resolution scenarios where QNAME minimization and forwarding were both enabled (bsc#1175443).
  • CVE-2020-8620: It was possible to trigger an assertion failure by sending a specially crafted large TCP DNS message (bsc#1175443).
  • CVE-2020-8622: It was possible to trigger an assertion failure when verifying the response to a TSIG-signed request (bsc#1175443).

Other issues fixed:

  • Add engine support to OpenSSL EdDSA implementation.
  • Add engine support to OpenSSL ECDSA implementation.
  • Update PKCS#11 EdDSA implementation to PKCS#11 v3.0.
  • Warn about AXFR streams with inconsistent message IDs.
  • Make ISC rwlock implementation the default again.
  • Fixed issues when using cookie-secrets for AES and SHA2 (bsc#1161168)
  • Installed the default files in /var/lib/named and created chroot environment on systems using transactional-updates (bsc#1100369, fate#325524)
  • Fixed an issue where bind was not working in FIPS mode (bsc#906079).
  • Fixed dependency issues (bsc#1118367 and bsc#1118368).
  • GeoIP support is now discontinued, now GeoIP2 is used(bsc#1156205).
  • Fixed an issue with FIPS (bsc#1128220).
  • The liblwres library is discontinued upstream and is no longer included.
  • Added service dependency on NTP to make sure the clock is accurate when bind is starts (bsc#1170667, bsc#1170713).
  • Reject DS records at the zone apex when loading master files. Log but otherwise ignore attempts to add DS records at the zone apex via UPDATE.
  • The default value of 'max-stale-ttl' has been changed from 1 week to 12 hours.
  • Zone timers are now exported via statistics channel.
  • The 'primary' and 'secondary' keywords, when used as parameters for 'check-names', were not processed correctly and were being ignored.
  • 'rndc dnstap -roll <value>' did not limit the number of saved files to <value>.
  • Add 'rndc dnssec -status' command.
  • Addressed a couple of situations where named could crash.
  • Changed /var/lib/named to owner root:named and perms rwxrwxr-t so that named, being a/the only member of the 'named' group has full r/w access yet cannot change directories owned by root in the case of a compromized named. [bsc#1173307, bind-chrootenv.conf]
  • Added…
Record
openSUSE-SU-2020:1701-1
Updated
2026-11-02
OSVopenSUSE-SU-2024:10650-1 No score

bind-9.16.20-1.4 on GA media

These are all security issues fixed in the bind-9.16.20-1.4 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:10650-1
Updated
2026-11-02
OSVSUSE-SU-2020:2914-1 No score

Security update for bind

This update for bind fixes the following issues:

BIND was upgraded to version 9.16.6:

Note:

  • bind is now more strict in regards to DNSSEC. If queries are not working, check for DNSSEC issues. For instance, if bind is used in a namserver forwarder chain, the forwarding DNS servers must support DNSSEC.

Fixing security issues:

  • CVE-2020-8616: Further limit the number of queries that can be triggered from a request. Root and TLD servers are no longer exempt from max-recursion-queries. Fetches for missing name server. (bsc#1171740) Address records are limited to 4 for any domain.
  • CVE-2020-8617: Replaying a TSIG BADTIME response as a request could trigger an assertion failure. (bsc#1171740)
  • CVE-2019-6477: Fixed an issue where TCP-pipelined queries could bypass the tcp-clients limit (bsc#1157051).
  • CVE-2018-5741: Fixed the documentation (bsc#1109160).
  • CVE-2020-8618: It was possible to trigger an INSIST when determining whether a record would fit into a TCP message buffer (bsc#1172958).
  • CVE-2020-8619: It was possible to trigger an INSIST in lib/dns/rbtdb.c:new_reference() with a particular zone content and query patterns (bsc#1172958).
  • CVE-2020-8624: 'update-policy' rules of type 'subdomain' were incorrectly treated as 'zonesub' rules, which allowed keys used in 'subdomain' rules to update names outside of the specified subdomains. The problem was fixed by making sure 'subdomain' rules are again processed as described in the ARM (bsc#1175443).
  • CVE-2020-8623: When BIND 9 was compiled with native PKCS#11 support, it was possible to trigger an assertion failure in code determining the number of bits in the PKCS#11 RSA public key with a specially crafted packet (bsc#1175443).
  • CVE-2020-8621: named could crash in certain query resolution scenarios where QNAME minimization and forwarding were both enabled (bsc#1175443).
  • CVE-2020-8620: It was possible to trigger an assertion failure by sending a specially crafted large TCP DNS message (bsc#1175443).
  • CVE-2020-8622: It was possible to trigger an assertion failure when verifying the response to a TSIG-signed request (bsc#1175443).

Other issues fixed:

  • Add engine support to OpenSSL EdDSA implementation.
  • Add engine support to OpenSSL ECDSA implementation.
  • Update PKCS#11 EdDSA implementation to PKCS#11 v3.0.
  • Warn about AXFR streams with inconsistent message IDs.
  • Make ISC rwlock implementation the default again.
  • Fixed issues when using cookie-secrets for AES and SHA2 (bsc#1161168)
  • Installed the default files in /var/lib/named and created chroot environment on systems using transactional-updates (bsc#1100369, fate#325524)
  • Fixed an issue where bind was not working in FIPS mode (bsc#906079).
  • Fixed dependency issues (bsc#1118367 and bsc#1118368).
  • GeoIP support is now discontinued, now GeoIP2 is used(bsc#1156205).
  • Fixed an issue with FIPS (bsc#1128220).
  • The liblwres library is discontinued upstream and is no longer included.
  • Added service dependency on NTP to make sure the clock is accurate when bind is starts (bsc#1170667, bsc#1170713).
  • Reject DS records at the zone apex when loading master files. Log but otherwise ignore attempts to add DS records at the zone apex via UPDATE.
  • The default value of 'max-stale-ttl' has been changed from 1 week to 12 hours.
  • Zone timers are now exported via statistics channel.
  • The 'primary' and 'secondary' keywords, when used as parameters for 'check-names', were not processed correctly and were being ignored.
  • 'rndc dnstap -roll <value>' did not limit the number of saved files to <value>.
  • Add 'rndc dnssec -status' command.
  • Addressed a couple of situations where named could crash.
  • Changed /var/lib/named to owner root:named and perms rwxrwxr-t so that named, being a/the only member of the 'named' group has full r/w access yet cannot change directories owned by root in the case of a compromized named. [bsc#1173307, bind-chrootenv.conf]
  • Added…
Record
SUSE-SU-2020:2914-1
Updated
2026-11-02
OSVUSN-4399-1 No score

bind9 vulnerabilities

It was discovered that Bind incorrectly handled large responses during zone transfers. A remote attacker could possibly use this issue to cause Bind to crash, resulting in a denial of service. (CVE-2020-8618)

It was discovered that Bind incorrectly handled certain asterisk characters in zone files. A remote attacker could possibly use this issue to cause Bind to crash, resulting in a denial of service. (CVE-2020-8619)

Record
USN-4399-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
bind
Alpine:v3.10
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.11
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.12
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.13
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.14
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.15
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.16
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.17
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.18
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.19
9.16.0 up to 9.16.4-r0
9.16.4-r0
Show 31 moreShow less
Affected packages
PackageAffectedFixed
bind
Alpine:v3.20
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.21
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.22
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.23
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind
Alpine:v3.24
9.16.0 up to 9.16.4-r0
9.16.4-r0
bind9
Debian:12
before 1:9.16.4-1
1:9.16.4-1
bind9
Debian:13
before 1:9.16.4-1
1:9.16.4-1
bind9
Debian:14
before 1:9.16.4-1
1:9.16.4-1
bind
SUSE:Linux Enterprise Module for Basesystem 15 SP1
before 9.16.6-12.32.1
9.16.6-12.32.1
sysuser-tools
SUSE:Linux Enterprise Module for Basesystem 15 SP1
before 2.0-4.2.8
2.0-4.2.8
bind
SUSE:Linux Enterprise Module for Basesystem 15 SP2
before 9.16.6-12.32.1
9.16.6-12.32.1
sysuser-tools
SUSE:Linux Enterprise Module for Basesystem 15 SP2
before 2.0-4.2.8
2.0-4.2.8
sysuser-tools
SUSE:Linux Enterprise Module for Development Tools 15 SP2
before 2.0-4.2.8
2.0-4.2.8
bind
SUSE:Linux Enterprise Module for Server Applications 15 SP1
before 9.16.6-12.32.1
9.16.6-12.32.1
bind
SUSE:Linux Enterprise Module for Server Applications 15 SP2
before 9.16.6-12.32.1
9.16.6-12.32.1
bind
SUSE:Linux Enterprise High Performance Computing 15-ESPOS
before 9.16.6-12.32.1
9.16.6-12.32.1
sysuser-tools
SUSE:Linux Enterprise High Performance Computing 15-ESPOS
before 2.0-4.2.8
2.0-4.2.8
bind
SUSE:Linux Enterprise High Performance Computing 15-LTSS
before 9.16.6-12.32.1
9.16.6-12.32.1
sysuser-tools
SUSE:Linux Enterprise High Performance Computing 15-LTSS
before 2.0-4.2.8
2.0-4.2.8
bind
SUSE:Linux Enterprise Server 15-LTSS
before 9.16.6-12.32.1
9.16.6-12.32.1
sysuser-tools
SUSE:Linux Enterprise Server 15-LTSS
before 2.0-4.2.8
2.0-4.2.8
bind
SUSE:Linux Enterprise Server for SAP Applications 15
before 9.16.6-12.32.1
9.16.6-12.32.1
sysuser-tools
SUSE:Linux Enterprise Server for SAP Applications 15
before 2.0-4.2.8
2.0-4.2.8
bind9
Ubuntu:20.04:LTS
before 1:9.16.1-0ubuntu2.2, plus listed versions
1:9.11.5.P4+dfsg-5.1ubuntu21:9.11.5.P4+dfsg-5.1ubuntu31:9.11.5.P4+dfsg-5.1ubuntu41:9.11.5.P4+dfsg-5.1ubuntu51:9.11.14+dfsg-1ubuntu1
Show 7 moreShow less
1:9.11.14+dfsg-3ubuntu11:9.16.0-1ubuntu31:9.16.0-1ubuntu41:9.16.0-1ubuntu51:9.16.1-0ubuntu11:9.16.1-0ubuntu21:9.16.1-0ubuntu2.1
1:9.16.1-0ubuntu2.2
bind
openSUSE:Leap 15.2
before 9.16.6-lp152.14.3.1
9.16.6-lp152.14.3.1
libuv
openSUSE:Leap 15.2
before 1.18.0-lp152.4.3.1
1.18.0-lp152.4.3.1
sysuser-tools
openSUSE:Leap 15.2
before 2.0-lp152.5.3.1
2.0-lp152.5.3.1
bind
openSUSE:Leap 15.1
before 9.16.6-lp151.11.9.1
9.16.6-lp151.11.9.1
libuv
openSUSE:Leap 15.1
before 1.18.0-lp151.3.3.1
1.18.0-lp151.3.3.1
sysuser-tools
openSUSE:Leap 15.1
before 2.0-lp151.4.3.1
2.0-lp151.4.3.1
bind
openSUSE:Tumbleweed
before 9.16.20-1.4
9.16.20-1.4

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2020-8618 is a medium vulnerability (CVSS 4.9) in Canonical Ubuntu Linux, published June 17, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.88%, the 79th percentile. Fixed in bind 9.16.4-r0.

References

Show 65 moreShow less
This page doesn't list everything

Left out here: the rest of 3 source descriptions. The JSON record has them.

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