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Vulnerability record · CVE-2024-53861 · published 29 November 2024

CVE-2024-53861: Pyjwt project pyjwt vulnerability

Pyjwt Project · Pyjwt

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.

7.5 CVSS 3.1 High EPSS 0.83% · top 44.1% CWE-697 · CWE-697
7.5CVSS 3.1 base score
0.83%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 1 tagged exploit
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/jpadilla/pyjwt/commit/1570e708672aa9036bc772476beae8bfa48f4131#diff-6893ad4a1c5a36b8af3028db8c8bc3b62 Patch
https://github.com/jpadilla/pyjwt/commit/33022c25525c1020869c71ce2a4109e44ae4ced1 Patch
https://github.com/jpadilla/pyjwt/security/advisories/GHSA-75c5-xw7c-p5pm ExploitVendor Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2024-53861), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.