PyJWKClient: missing scheme allowlist enables CVE-2024-21643-class SSRF + token forgery via file://, ftp://, data: schemes

!NOTE The library does not directly return non-HTTPS URI contents to the attacker; the chained "plant a JWKS to forge tokens" scenario described in the original report requires additional application-layer flaws attacker write access to a filesystem path, untrusted jku derivation that this fix do...

PYSEC-0000-CVE-2026-48522

PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, PyJWKClient passes its uri argument directly to urllib.request.urlopen which uses Python stdlib's default OpenerDirector registering HTTPHandler, HTTPSHandler, FTPHandler, FileHandler, and DataHandler. There is currently no...