CVE-2026-102268
Consequently, an attacker who knows the public key can forge authenticated HMAC tokens.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.24%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.24% probability · 14th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-347
- Affected
- pyjwt project/pyjwt
- Source
- security-advisories@github.com
EPSS moved from 0.2% on 29 September 2026 to 0.2% on 26 October 2026.
References
- https://github.com/jpadilla/pyjwt/commit/8b4e233a22206b34ec1186e912e75c0b2396ac07Patch
- https://github.com/jpadilla/pyjwt/releases/tag/2.14.0Product, Release Notes
- https://github.com/jpadilla/pyjwt/security/advisories/GHSA-ffc3-869f-jxw9Exploit, Vendor Advisory
- https://github.com/jpadilla/pyjwt/security/advisories/GHSA-ffc3-869f-jxw9Exploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.