← Vulnerability feed

Vulnerability record · CVE-2026-102268 · published 28 September 2026

CVE-2026-102268: Pyjwt project pyjwt improper verification of cryptographic signature vulnerability

Pyjwt Project · Pyjwt

PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, is_pem_format in jwt/utils.py is affected because is_pem_format does not recognize every PEM representation accepted by the cryptography loader. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a mutated public-key PEM as raw key bytes. As a result, HMACAlgorithm.prepare_key treats the unrecognized asymmetric public key 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.

9.1 CVSS 3.1 Critical EPSS 0.20% · top 90.7% CWE-347 · Improper verification of cryptographic signature
9.1CVSS 3.1 base score
0.20%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 2 tagged exploit
7 Oct 2026Last modified by NVD

Description

PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, is_pem_format in jwt/utils.py is affected because is_pem_format does not recognize every PEM representation accepted by the cryptography loader. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a mutated public-key PEM as raw key bytes. As a result, HMACAlgorithm.prepare_key treats the unrecognized asymmetric public key 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.

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

Affected products

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

References

LinkTags
https://github.com/jpadilla/pyjwt/commit/8b4e233a22206b34ec1186e912e75c0b2396ac07 Patch
https://github.com/jpadilla/pyjwt/releases/tag/2.14.0 ProductRelease Notes
https://github.com/jpadilla/pyjwt/security/advisories/GHSA-ffc3-869f-jxw9 ExploitVendor Advisory
https://github.com/jpadilla/pyjwt/security/advisories/GHSA-ffc3-869f-jxw9 ExploitVendor Advisory

Track CVE-2026-102268 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

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

9.1CVE-2026-102267Pyjwt project pyjwt information exposure vulnerabilityPyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT PyJWKClient is affected because redirect destinations are not re…EPSS 0.16%9.1CVE-2026-102266Pyjwt project pyjwt improper verification of cryptographic signature vulnerabilityPyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification…EPSS 0.18%8.2CVE-2026-102275Pyjwt project pyjwt insufficient verification of data authenticity vulnerabilityPyJWT is a Python implementation of JSON Web Token standards. From 2.1.0 until 2.15.0, PyJWT OKPAlgorithm.from_jwk in jwt/algorithms.py is affected b…EPSS 0.14%7.5CVE-2026-102274Pyjwt project pyjwt vulnerabilityPyJWT is a Python implementation of JSON Web Token standards. From 2.9.0 until 2.14.0, PyJWKSet does not catch the plain ValueError raised for malfor…EPSS 0.39%7.5CVE-2026-101918Pyjwt project pyjwt vulnerabilityPyJWT is a Python implementation of JSON Web Token standards. From 2.0.0a1 until 2.15.0, PyJWT PyJWKClient.get_signing_key_from_jwt is affected becau…EPSS 0.36%7.5CVE-2026-101917Pyjwt project pyjwt allocation without limits vulnerabilityPyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT get_signing_key_from_jwt is affected because unknown kid misses …EPSS 0.42%7.5CVE-2026-32597Pyjwt project pyjwt insufficient verification of data authenticity vulnerabilityPyJWT is a JSON Web Token implementation in Python. Prior to 2.12.0, PyJWT does not validate the crit (Critical) Header Parameter defined in RFC 7515…EPSS 0.28%7.5CVE-2024-53861Pyjwt project pyjwt vulnerabilitypyjwt is a JSON Web Token implementation in Python. An incorrect string comparison is run for `iss` checking, resulting in `"acb"` being accepted for…EPSS 0.83%

Source: NIST National Vulnerability Database (record CVE-2026-102268), CISA KEV, FIRST EPSS (scores of 2026-10-08). This page is refreshed as NVD updates the record.