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Vulnerability · Published Jun 21, 2023 · Assigned by isc

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

High 7.5

In plain English

A high-severity security flaw in BIND 9 from ISC. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.4% (higher than 84% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)2.4%top 15.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

If the `recursive-clients` quota is reached on a BIND 9 resolver configured with both `stale-answer-enable yes;` and `stale-answer-client-timeout 0;`, a sequence of serve-stale-related lookups could cause `named` to loop and terminate unexpectedly due to a stack overflow. This issue affects BIND 9 versions 9.16.33 through 9.16.41, 9.18.7 through 9.18.15, 9.16.33-S1 through 9.16.41-S1, and 9.18.11-S1 through 9.18.15-S1.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12bind91:9.18.16-1~deb12u1DEBIAN-CVE-2023-2911
Debian:12bind91:9.18.16-1~deb12u1DSA-5439-1
Debian:13bind91:9.18.16-1DEBIAN-CVE-2023-2911
Debian:14bind91:9.18.16-1DEBIAN-CVE-2023-2911
Ubuntu:22.04:LTSbind91:9.18.12-0ubuntu0.22.04.2USN-6183-1
Ubuntu:22.04:LTSbind91:9.18.12-0ubuntu0.22.04.2UBUNTU-CVE-2023-2911

Affected products (as reported)

VendorProductVersions
ISC BIND 9 9.16.33 – through 9.16.419.18.7 – through 9.18.159.16.33-S1 – through 9.16.41-S19.18.11-S1 – through 9.18.15-S1

References