high7.4
CVE-2026-102271
PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217 guard
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | pyjwt | >= 2.4.0, < 2.14.0 | 2.14.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Pyjwt Project | Pyjwt | from 2.4.0 before 2.14.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-p4g4-x82p-q773
- https://github.com/jpadilla/pyjwt/security/advisories/GHSA-p4g4-x82p-q773
- https://nvd.nist.gov/vuln/detail/CVE-2026-102271
- https://github.com/jpadilla/pyjwt/commit/2798504fa2663364573cf2d1043d8d7fef389499
- https://github.com/jpadilla/pyjwt/releases/tag/2.14.0