CVE-2023-2911: Exceeding the recursive-clients quota may cause named to terminate unexpectedly when stale-answer-client-timeout is set to 0

Reference Links

• https://kb.isc.org/docs/cve-2023-2911
• http://www.openwall.com/lists/oss-security/2023/06/21/6
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U3K6AJK7RRSR53HRF5GGKPA6PDUDWOD2/
• https://www.debian.org/security/2023/dsa-5439
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SEFCEVCTYEMKTWA7V7EYPI5YQQ4JWDLI/
• https://security.netapp.com/advisory/ntap-20230703-0010/
• https://launchpad.net/bugs/cve/CVE-2023-2911
• https://downloads.isc.org/isc/bind9/9.18.16/patches/0003-CVE-2023-2911.patch
• https://downloads.isc.org/isc/bind9/9.16.42/patches/0003-CVE-2023-2911.patch
• https://security-tracker.debian.org/tracker/CVE-2023-2911
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-2911
• https://kb.isc.org/v1/docs/cve-2023-2911
• https://ubuntu.com/security/notices/USN-6183-1
• https://nvd.nist.gov/vuln/detail/CVE-2023-2911
• https://ubuntu.com/security/CVE-2023-2911

Parent vulnerabilities

(Appears in the following advisories)

• USN-6183-1

Frequently Asked Questions

• What is CVE-2023-2911?

  CVE-2023-2911 is a vulnerability that affects BIND 9 resolvers configured with both `stale-answer-enable yes;` and `stale-answer-client-timeout 0;`.

• How does CVE-2023-2911 affect BIND 9?

  CVE-2023-2911 can cause `named` to loop and terminate unexpectedly due to a stack overflow if the `recursive-clients` quota is reached.

• Which versions of BIND 9 are affected by CVE-2023-2911?

  BIND 9 versions 9.16.1-0ubuntu2.15, 9.18.12-0ubuntu0.22.04.2, 9.18.12-0ubuntu0.22.10.2, 9.18.12-1ubuntu1.1, 9.16.42, 9.18.16, 9.11.5.P4+dfsg-5.1+deb10u7, 9.11.5.P4+dfsg-5.1+deb10u9, 9.16.44-1~deb11u1, 9.18.16-1~deb12u1, 9.18.19-1~deb12u1, and 9.19.17 are affected.

• What is the severity of CVE-2023-2911?

  The severity of CVE-2023-2911 is not specified in the provided information.

• How do I fix CVE-2023-2911?

  To fix CVE-2023-2911, update BIND 9 to a version that includes the necessary security patch.

• Where can I find more information about CVE-2023-2911?

  You can find more information about CVE-2023-2911 at the following references: - [ISC Knowledge Base](https://kb.isc.org/docs/cve-2023-2911) - [Openwall Mailing List](http://www.openwall.com/lists/oss-security/2023/06/21/6) - [Fedora Project Package Announce Mailing List](https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U3K6AJK7RRSR53HRF5GGKPA6PDUDWOD2/)