CVE-2026-5246

Name	CVE-2026-5246
Description	A vulnerability was determined in Cesanta Mongoose up to 7.20. Affected is the function mg_tls_verify_cert_signature of the file mongoose.c of the component P-384 Public Key Handler. Executing a manipulation can lead to authorization bypass. The attack can be executed remotely. Attacks of this nature are highly complex. The exploitability is told to be difficult. The exploit has been publicly disclosed and may be utilized. Upgrading to version 7.21 is able to address this issue. This patch is called 0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1. The affected component should be upgraded. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.
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
mongoose (PTS)	forky, sid	7.21+ds-2	fixed
swupdate (PTS)	bullseye	2020.11-2+deb11u1	vulnerable
	bookworm	2022.12+dfsg-4+deb12u2	vulnerable
	trixie	2024.12.1+dfsg-3+deb13u2	vulnerable
	forky, sid	2025.12+dfsg-10	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
mongoose	source	(unstable)	(not affected)
swupdate	source	(unstable)	2025.12+dfsg-10

Notes

- mongoose <not-affected> (Fixed before or with initial upload)
[trixie] - swupdate <no-dsa> (Minor issue)
[bookworm] - swupdate <no-dsa> (Minor issue)
[bullseye] - swupdate <postponed> (Minor issue)