CVE-2023-6516

Name	CVE-2023-6516
Description	To keep its cache database efficient, `named` running as a recursive resolver occasionally attempts to clean up the database. It uses several methods, including some that are asynchronous: a small chunk of memory pointing to the cache element that can be cleaned up is first allocated and then queued for later processing. It was discovered that if the resolver is continuously processing query patterns triggering this type of cache-database maintenance, `named` may not be able to handle the cleanup events in a timely manner. This in turn enables the list of queued cleanup events to grow infinitely large over time, allowing the configured `max-cache-size` limit to be significantly exceeded. This issue affects BIND 9 versions 9.16.0 through 9.16.45 and 9.16.8-S1 through 9.16.45-S1.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
bind9 (PTS)	bullseye	1:9.16.50-1~deb11u2	fixed
	bullseye (security)	1:9.16.50-1~deb11u1	fixed
	bookworm, bookworm (security)	1:9.18.28-1~deb12u2	fixed
	trixie	1:9.20.4-2	fixed
	sid	1:9.20.4-3	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version
bind9	source	buster	(not affected)
bind9	source	bullseye	1:9.16.48-1
bind9	source	(unstable)	1:9.17.19-1

Notes

[buster] - bind9 <not-affected> (Vulnerable code only in 9.16.y series)
https://kb.isc.org/docs/cve-2023-6516
Issue is specific to 9.16.y. Mark the first version from 9.17.y series
which entered unstable as the fixed version as workaround.