CVE-2024-53861

Name	CVE-2024-53861
Description	pyjwt is a JSON Web Token implementation in Python. An incorrect string comparison is run for `iss` checking, resulting in `"acb"` being accepted for `"_abc_"`. This is a bug introduced in version 2.10.0: checking the "iss" claim changed from `isinstance(issuer, list)` to `isinstance(issuer, Sequence)`. Since str is a Sequnce, but not a list, `in` is also used for string comparison. This results in `if "abc" not in "__abcd__":` being checked instead of `if "abc" != "__abc__":`. Signature checks are still present so real world impact is likely limited to denial of service scenarios. This issue has been patched in version 2.10.1. All users are advised to upgrade. There are no known workarounds for this vulnerability.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, 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)	jessie, jessie (lts)	0.2.1-1+deb8u2	fixed
	stretch (security), stretch (lts), stretch	1.4.2-1+deb9u1	fixed
	buster	1.7.0-2	fixed
	bullseye	1.7.1-2	fixed
	bookworm	2.6.0-1	fixed
	trixie	2.7.0-1	fixed
	sid	2.10.1-2	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)	(not affected)

Notes

- pyjwt <not-affected> (Vulnerable code introduced in 2.10.0)
https://github.com/jpadilla/pyjwt/security/advisories/GHSA-75c5-xw7c-p5pm
https://github.com/jpadilla/pyjwt/commit/33022c25525c1020869c71ce2a4109e44ae4ced1 (2.10.1)