CVE-2026-42784

Name	CVE-2026-42784
Description	A flaw was found in sequoia-openpgp. The library incorrectly infers key flags for older certificates when a key flags subpacket is missing, leading to a discrepancy in how key capabilities are viewed. This key flag confusion allows an attacker to bypass the back-signature check. Consequently, an attacker can illegitimately bind an arbitrary subkey to their own certificate and forge signatures, completely compromising cryptographic integrity.
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)
Debian Bugs	1137328

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
rust-sequoia-openpgp (PTS)	bookworm	1.12.0-2	vulnerable
	trixie	2.0.0-2+deb13u1	vulnerable
	forky, sid	2.4.1-2	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
rust-sequoia-openpgp	source	(unstable)	2.2.0-2			1137328

Notes

[trixie] - rust-sequoia-openpgp <no-dsa> (Minor issue)
[bookworm] - rust-sequoia-openpgp <no-dsa> (Minor issue)
[bullseye] - rust-sequoia-openpgp <postponed> (Minor issue)
Fixed by: https://gitlab.com/sequoia-pgp/sequoia/-/commit/58214b47b110e110432731f8fc5dec71918c4254 (openpgp/v2.3.0)