CVE-2026-101917: medium-severity vulnerability in jpadilla pyjwt
PyJWT: PyJWKClient still amplifies unauthenticated JWKS fetches on unknown kid values (incomplete fix of CVE-2026-48524)
Published
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.4%
exploitation probability
0.4%top 73% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Affected products
jpadilla · pyjwtRelated CVEs — jpadilla pyjwt
In the same product, most dangerous first.
CVE-2022-29217HIGHKey confusion through non-blocklisted public key formats in PyJWTEPSS 1.4%CVE-2024-53861LOWIssuer field partial matches allowed in pyjwtEPSS 0.8%CVE-2026-48526HIGHPyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowedEPSS 0.4%CVE-2026-48525MEDIUMPyJWT: Unauthenticated DoS via unbounded Base64URL decoding of unused payload segment in b64=false detached JWSEPSS 0.4%CVE-2026-102274MEDIUMPyJWT: Malformed RSA JWK aborts parsing of an entire JWK SetEPSS 0.4%CVE-2026-48524LOWPyJWT: PyJWKClient unbounded JWKS endpoint requests via attacker-controlled kid values (DoS)EPSS 0.3%