GHSA-5739-39v2-5754Medium▾ SunlitPHP JWT Library: RSA1_5 (RSAES-PKCS1-v1_5) decryption lacks implicit rejection, exposing a Bleichenbacher/Marvin padding oracle
▾ Sunlit zone — Low / medium · no exploitation signal
impact 27.5 · likelihood 0 · exploitation 0
Need a working PoC? Pro members can cast a request and our team develops one — it lands right here.
RSACrypt::decryptWithRSA15() (used by the RSA1_5 key-encryption algorithm) implements RSAES-PKCS1-v1_5 decryption by inspecting the padding after RSADP and throwing InvalidArgumentException as soon as the padding is malformed. It does not implement the implicit-rejection countermeasure required by RFC 3447 §7.2.2 / RFC 8017 §7.1.2 (return a deterministic pseudo-random value of the expected length on padding failure and let the downstream step fail uniformly).
From a JWE caller this yields a Bleichenbacher/Marvin padding oracle: an attacker submitting adaptively crafted encrypted_key values can distinguish (a) padding rejected, (b) padding valid but wrong CEK length, and (c) padding valid and full AEAD executed — even though JWEDecrypter returns the same false in all cases — because each path performs a measurably different amount of work, amplifiable by enlarging the ciphertext (CWE-208 timing side channel). Enough adaptive queries can recover the wrapped CEK.
Applications that register RSA1_5 in their decryption AlgorithmManager and hold an RSA private key.
PKCS#1 v1.5 decryption now performs implicit rejection: on invalid padding (or unexpected recovered length) it returns a random CEK of the expected size selected in constant time, so the full content-decryption (AEAD) step always runs and fails uniformly, removing the observable difference between padding-valid and padding-invalid ciphertexts. Users are still strongly encouraged to migrate to RSA-OAEP.
Prefer RSA-OAEP/RSA-OAEP-256; do not enable RSA1_5 for untrusted tokens.
Un correctif a été préparé sur une branche dédiée basée sur 3.4.x, avec des tests anti-régression dédiés (fork privé temporaire de cette advisory, PR #1).
RSA1_5 — déchiffrement PKCS#1 v1.5 avec implicit rejection en temps constant (RFC 3447 §7.2.2) : un padding invalide n'est plus distinguable d'un padding valide, neutralisant l'oracle Bleichenbacher.
Validation : php -l OK, PHPUnit vert, aucune nouvelle erreur PHPStan introduite (différentiel nul vs 3.4.x), aucun commentaire ajouté dans le code source. Après merge, cascade prévue 3.4.x → 4.0.x → 4.1.x.
web-token/jwt-library < 3.4.10web-token/jwt-framework <= 4.1.6web-token/jwt-library >= 4.0.0, < 4.0.7web-token/jwt-library >= 4.1.0, < 4.1.7Upgrade to a patched release:
web-token/jwt-library 3.4.10web-token/jwt-library 4.0.7web-token/jwt-library 4.1.7Connected by shared product, vendor, weakness, or advisory.
GHSA-3prj-6hqw-cm82HighPHP JWT Library: PBES2-HS*+A*KW unwrap accepts an unbounded p2c iteration count, enabling CPU-amplification denial of service
CVE-2026-84308Medium· 6.3phpseclib is a PHP secure communications library
CVE-2026-55785Low· 3.7free5GC is an open-source implementation of the 5G core network
CVE-2026-6478Medium· 6.5Covert timing channel in comparison of MD5-hashed password in PostgreSQL authentication allows an attacker to recover user credentials sufficient to authenticate
GHSA-6vvh-pxr4-25r7MediumPHP JWT Framework: Chacha20Poly1305 key-encryption algorithm discards the Poly1305 authentication tag, performing no authentication on decryption
GHSA-jc38-x7x8-2xc8HighPHP JWT Framework: JWSVerifier uses algorithm from unprotected header, enabling algorithm confusion attacks