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.
The product compares two entities in a security-relevant context, but the comparison is incorrect, which may lead to resultant weaknesses.
This Pillar covers several possibilities: