CVE-2026-33811

Name	CVE-2026-33811
Description	When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash.
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)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
golang-1.15 (PTS)	bullseye	1.15.15-1~deb11u4	vulnerable
golang-1.19 (PTS)	bookworm	1.19.8-2	vulnerable
golang-1.24 (PTS)	trixie	1.24.4-1	vulnerable
golang-1.25 (PTS)	forky, sid	1.25.10-2	fixed
golang-1.26 (PTS)	forky, sid	1.26.3-2	fixed

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

Package	Type	Release	Fixed Version
golang-1.15	source	(unstable)	(unfixed)
golang-1.19	source	(unstable)	(unfixed)
golang-1.24	source	(unstable)	(unfixed)
golang-1.25	source	(unstable)	1.25.10-1
golang-1.26	source	(unstable)	1.26.3-1

Notes

[bullseye] - golang-1.15 <postponed> (Limited support, follow bookworm DSAs/point-releases)
https://go-review.googlesource.com/c/go/+/767860
https://github.com/golang/go/issues/78803
https://groups.google.com/g/golang-announce/c/qcCIEXso47M