CVE-2026-102271

Name	CVE-2026-102271
Description	PyJWT is a Python implementation of JSON Web Token standards. From 2.4.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because asymmetric-key guard relies on textual markers that are absent from DER encoding. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a DER public key as the shared verification key. As a result, PyJWT uses public DER bytes as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.
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
pyjwt (PTS)	bookworm, bookworm (security)	2.6.0-1+deb12u1	vulnerable
	trixie (security), trixie	2.10.1-2+deb13u1	vulnerable
	forky	2.13.0-1	vulnerable
	sid	2.15.1-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
pyjwt	source	(unstable)	2.14.0-1

Notes

https://github.com/jpadilla/pyjwt/security/advisories/GHSA-p4g4-x82p-q773
Fixed by: https://github.com/jpadilla/pyjwt/commit/2798504fa2663364573cf2d1043d8d7fef389499 (2.14.0)