CVE-2026-101917CWE-770denial-of-service

CVE-2026-101917

Medium · published September 29, 2026

CVSS v3.1
5.3
EPSS
0%
Percentile
35.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00418 · 35.1th percentile
Weakness
CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-09-29T01:17Z
Affected products (1)
ProductVersionsFixed in
pyjwt_project/pyjwt< 2.14.02.14.0
References (4)
https://github.com/jpadilla/pyjwt/commit/ba4853a75fb9676362da17f67d0f64bd18afd4e1 · [email protected]https://github.com/jpadilla/pyjwt/releases/tag/2.14.0 · [email protected]https://github.com/jpadilla/pyjwt/security/advisories/GHSA-2gx3-rcp4-g85q · [email protected]https://github.com/jpadilla/pyjwt/security/advisories/GHSA-2gx3-rcp4-g85q · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 30 SEP 03:24Z
    EPSS moved — → 0%
    epss
  • 28 SEP 20:07Z
    PyJWT: PyJWKClient still amplifies unauthenticated JWKS fetches on unknown kid values (incomplete fix of CVE-2026-48524)
    cvelistv5