CVE-2026-6679

Name	CVE-2026-6679
Description	A heap buffer overflow could occur in the DTLS 1.3 ACK serialization path before the connecting peer is authenticated. The buffer overflow was due to an integer truncation when computing the length of the ACK record-number list, causing an undersized buffer to be allocated and then overrun. This affects builds using DTLS 1.3 and wolfSSL version 5.9.0 and earlier. A fix was added to the 5.9.1 release.
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
wolfssl (PTS)	bullseye	4.6.0+p1-0+deb11u2	vulnerable
	bookworm	5.5.4-2+deb12u2	vulnerable
	trixie	5.7.2-0.1+deb13u1	vulnerable
	forky, sid	5.9.1-0.1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
wolfssl	source	(unstable)	5.9.1-0.1

https://github.com/wolfSSL/wolfssl/pull/10116 (v5.9.1-stable)