CVE-2026-49852

NameCVE-2026-49852
Descriptionjoserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.6.8, joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the caller-supplied verification key is the empty string or None, because HMACAlgorithm.sign and HMACAlgorithm.verify in src/joserfc/_rfc7518/jws_algs.py pass the output of OctKey.get_op_key(...) to hmac.new(...) and OctKey.import_key in src/joserfc/_rfc7518/oct_key.py only emits a SecurityWarning for keys shorter than 14 bytes without rejecting zero-length input. This issue is fixed in version 1.6.8.
SourceCVE (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 PackageReleaseVersionStatus
joserfc (PTS)trixie1.1.0-1vulnerable
forky1.7.2-1fixed
sid1.7.3-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
joserfcsource(unstable)1.6.8-1

Notes

https://github.com/authlib/joserfc/security/advisories/GHSA-gg9x-qcx2-xmrh
Fixed by: https://github.com/authlib/joserfc/commit/86d00910b2b2d2d07503fee9b572906daefab7f1 (1.6.8)

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