{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "web-token/jwt-library"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.4.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "web-token/jwt-library"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "4.0.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "web-token/jwt-library"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.1.0"
            },
            {
              "fixed": "4.1.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-208",
      "CWE-385"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-18T21:09:56Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Impact\n\n`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 \u00a77.2.2 / RFC 8017 \u00a77.1.2 (return a deterministic pseudo-random value of the expected length on padding failure and let the downstream step fail uniformly).\n\nFrom 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 \u2014 even though `JWEDecrypter` returns the same `false` in all cases \u2014 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.\n\n### Affected configurations\n\nApplications that register `RSA1_5` in their decryption `AlgorithmManager` and hold an RSA private key.\n\n### Patches\n\nPKCS#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`.\n\n### Workarounds\n\nPrefer `RSA-OAEP`/`RSA-OAEP-256`; do not enable `RSA1_5` for untrusted tokens.\n\n### References\n\n- RFC 3447 \u00a77.2.2 / RFC 8017 \u00a77.1.2\n- Bleichenbacher (1998); Marvin attack\n- CWE-208: Observable Timing Discrepancy\n\n## R\u00e9solution\n\nUn correctif a \u00e9t\u00e9 pr\u00e9par\u00e9 sur une branche d\u00e9di\u00e9e bas\u00e9e sur `3.4.x`, avec des tests anti-r\u00e9gression d\u00e9di\u00e9s (fork priv\u00e9 temporaire de cette advisory, PR #1).\n\n**RSA1_5** \u2014 d\u00e9chiffrement PKCS#1 v1.5 avec *implicit rejection* en temps constant (RFC 3447 \u00a77.2.2) : un padding invalide n\u0027est plus distinguable d\u0027un padding valide, neutralisant l\u0027oracle Bleichenbacher.\n\n**Validation :** `php -l` OK, PHPUnit vert, aucune nouvelle erreur PHPStan introduite (diff\u00e9rentiel nul vs `3.4.x`), aucun commentaire ajout\u00e9 dans le code source. Apr\u00e8s merge, cascade pr\u00e9vue `3.4.x \u2192 4.0.x \u2192 4.1.x`.",
  "id": "GHSA-5739-39v2-5754",
  "modified": "2026-08-31T14:52:45Z",
  "published": "2026-06-18T21:09:56Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/web-token/jwt-framework/security/advisories/GHSA-5739-39v2-5754"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/web-token/jwt-library/GHSA-5739-39v2-5754.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/web-token/jwt-framework"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "PHP JWT Library: RSA1_5 (RSAES-PKCS1-v1_5) decryption lacks implicit rejection, exposing a Bleichenbacher/Marvin padding oracle"
}