CVE-2026-48524: low-severity vulnerability in jpadilla pyjwt
PyJWT: PyJWKClient unbounded JWKS endpoint requests via attacker-controlled kid values (DoS)
Published
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8Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 3.7epss 0.4%
PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, PyJWKClient.get_signing_key() forces a fresh HTTP request to the JWKS endpoint for every JWT with an unknown kid value, with no rate limiting. Since kid comes from the unverified token header, an attacker can trigger unlimited outbound requests. The vulnerability surfaces only when a JWKS fetch fails; an attacker can attempt to provoke that with sustained unknown-kid traffic, but the outcome depends on upstream JWKS-endpoint behavior (rate limiting, transient errors) which is beyond the attacker's control. This vulnerability is fixed in 2.13.0.
CVSS:3.1/AV:N/AC:H/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-2026-102274MEDIUMPyJWT: Malformed RSA JWK aborts parsing of an entire JWK SetEPSS 0.5%CVE-2026-101917MEDIUMPyJWT: PyJWKClient still amplifies unauthenticated JWKS fetches on unknown kid values (incomplete fix of CVE-2026-48524)EPSS 0.4%CVE-2026-48526HIGHPyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowedEPSS 0.4%CVE-2026-101918MEDIUMPyJWT: Unauthenticated RecursionError DoS in pre-verification payload parse (PyJWKClient.get_signing_key_from_jwt / verify_signature=False)EPSS 0.4%