CVE-2026-58218

Name	CVE-2026-58218
Description	A flaw was found in Samba's internal DNS server where unauthenticated TKEY registration requests were added to the TKEY name cache before being rejected. A remote, unauthenticated attacker can exploit this behavior by sending a large number of TKEY requests with arbitrary names, exhausting the cache and evicting legitimate TKEY entries. This can prevent legitimate TSIG authentication for signed DNS queries, resulting in a denial of service.
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	DSA-6401-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
samba (PTS)	bullseye	2:4.13.13+dfsg-1~deb11u6	vulnerable
	bullseye (security)	2:4.13.13+dfsg-1~deb11u8	vulnerable
	bookworm, bookworm (security)	2:4.17.12+dfsg-0+deb12u4	vulnerable
	trixie	2:4.22.10+dfsg-0+deb13u1	vulnerable
	trixie (security)	2:4.22.10+dfsg-0+deb13u2	fixed
	forky	2:4.24.5+dfsg-1	fixed
	sid	2:4.24.6+dfsg-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
samba	source	trixie	2:4.22.10+dfsg-0+deb13u2		DSA-6401-1
samba	source	(unstable)	2:4.24.5+dfsg-1

https://www.samba.org/samba/security/CVE-2026-58218-advisory.html