PYSEC-2026-4142 PyJWT: Uncaught RecursionError in jwt.decode() on deeply nested token header

Package pyjwt PyPI Affected versions tested & verified on: 2.13.0. Every version whose PyJWS.load translates only ValueError is affected Description PyJWS.looad jwt/apijws.py:337 splits the compact token, base64url decodes the header segment and hands it to json.loads before verifysignature runs...