CVE-2026-11622

Name	CVE-2026-11622
Description	A DNSSEC validating resolver that is under a random subdomain attack against a DNSSEC-signed zone can suffer from runaway memory usage. The attacker needs to be able to send queries faster than the resolver can perform validation. The increased memory usage can be orders of magnitude beyond the limit configured in the `max-cache-size` parameter. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-4725-1, DSA-6395-1

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	vulnerable
	bullseye (security)	1:9.16.50-1~deb11u6	fixed
	bookworm	1:9.18.49-1~deb12u1	vulnerable
	bookworm (security)	1:9.18.49-1~deb12u2	fixed
	trixie	1:9.20.23-1~deb13u1	vulnerable
	trixie (security)	1:9.20.26-1~deb13u1	fixed
	forky, sid	1:9.20.26-1	fixed

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

Package	Type	Release	Fixed Version	Origin
bind9	source	bullseye	1:9.16.50-1~deb11u6	DLA-4725-1
bind9	source	bookworm	1:9.18.49-1~deb12u2	DLA-4725-1
bind9	source	trixie	1:9.20.26-1~deb13u1	DSA-6395-1
bind9	source	(unstable)	1:9.20.26-1

Notes

https://kb.isc.org/docs/cve-2026-11622
https://gitlab.isc.org/isc-projects/bind9/-/commit/c57695da31a338092528283fde4f8ed9048b2087 (9.16-branch)
https://gitlab.isc.org/isc-projects/bind9/-/commit/231b1ca3edfb26389e1af39181aa6b4413e87ec4 (9.18-branch)