CVE-2026-102271High· 7.4▾ MidnightPoC availablePyJWT is a Python implementation of JSON Web Token standards. From 2.4.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because asymmetric-key guard relies on textual markers that are absent from DER encoding. This occurs when…
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 40.7 · likelihood 0 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Sep 29.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.2%
Exploit / PoC code exists
Last analysed / modified upstream
0.2% → 0.2%
PyJWT is a Python implementation of JSON Web Token standards. From 2.4.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because asymmetric-key guard relies on textual markers that are absent from DER encoding. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a DER public key as the shared verification key. As a result, PyJWT uses public DER bytes 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.
pyjwt >= 2.4.0, < 2.14.0Upgrade past the affected range:
pyjwt 2.14.0Affected packages:
pyjwt >= 2.4.0, < 2.14.0Patched in:
pyjwt 2.14.0Source: https://github.com/advisories/GHSA-p4g4-x82p-q773
Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
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