medium5.3
CVE-2026-101917
PyJWT: PyJWKClient still amplifies unauthenticated JWKS fetches on unknown kid values (incomplete fix of CVE-2026-48524)
Impact
PyJWT 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 force refreshes without a negative cache or minimum refresh interval. This occurs when unauthenticated tokens repeatedly use the same unknown kid or varying kid values absent from the cached JWKS. As a result, each cache miss causes PyJWKClient to refresh the JWKS. Consequently, attacker traffic can amplify outbound requests to the configured JWKS endpoint. This issue is fixed in version 2.14.0.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | pyjwt | <= 2.13.0 | 2.14.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Pyjwt Project | Pyjwt | before 2.14.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-2gx3-rcp4-g85q
- https://github.com/jpadilla/pyjwt/security/advisories/GHSA-2gx3-rcp4-g85q
- https://nvd.nist.gov/vuln/detail/CVE-2026-101917
- https://github.com/jpadilla/pyjwt/commit/ba4853a75fb9676362da17f67d0f64bd18afd4e1
- https://github.com/jpadilla/pyjwt/releases/tag/2.14.0