PyJWT: Asymmetric-PEM detection bypass: whitespace/line-ending-mutated public keys skip the HS/asymmetric confusion guard

PyJWT: PyJWKClient follows redirects when fetching JWKS

PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation

PyJWT accepts inconsistent OKP x/d JWKs, causing public/private key identity confusion

PyJWT: Malformed RSA JWK aborts parsing of an entire JWK Set

PyJWT: Unauthenticated RecursionError DoS in pre-verification payload parse (PyJWKClient.get_signing_key_from_jwt / verify_signature=False)

PyJWT: PyJWKClient still amplifies unauthenticated JWKS fetches on unknown kid values (incomplete fix of CVE-2026-48524)

PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)

PyJWT accepts public JWK containers as HMAC secrets

PyJWT BOM Bypass

PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217 guard

PyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowed

PyJWT.decode() reintroduces options-dict mutation, enabling silent claim-verification bypass on dict reuse

PyJWT: Non-canonical signature segments enable raw-token revocation bypass

PyJWT: Algorithm allow-list bypass when decoding with `PyJWK` / `PyJWKClient` keys

PyJWT: Uncaught RecursionError in jwt.decode() on deeply nested token header

PyJWT: Unauthenticated DoS via unbounded Base64URL decoding of unused payload segment in b64=false detached JWS

PyJWT: ReDoS vulnerability when calling the `is_pem_format` function.

PyJWKClient: missing scheme allowlist enables SSRF + token forgery via file://, ftp://, data: schemes

PyJWT: PyJWKClient unbounded JWKS endpoint requests via attacker-controlled kid values (DoS)