{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "web-token/jwt-experimental"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "4.1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "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-347",
      "CWE-353"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-18T21:08:15Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nThe experimental `Chacha20Poly1305` key-encryption algorithm generates the 16-byte Poly1305 authentication tag during `encryptKey()` but **discards it**: the tag is never written to the header and therefore never reaches the wire. On the receiving side, `decryptKey()` calls `openssl_decrypt(\u0027chacha20-poly1305\u0027, ...)` **without the tag argument**, which makes OpenSSL skip authentication entirely.\n\nAs a result the AEAD construction is silently degraded to unauthenticated ChaCha20: a tampered encrypted CEK is accepted, and because ChaCha20 is a stream cipher, a single-byte change in the ciphertext propagates as a single-byte change in the recovered CEK with no integrity check (CWE-353 / CWE-347). An attacker on the token path can manipulate the wrapped key without detection.\n\n### Affected configurations\n\nApplications that register `Jose\\Experimental\\KeyEncryption\\Chacha20Poly1305` (package `web-token/jwt-experimental`) as a JWE `alg`.\n\n### Patches\n\n`encryptKey()` now publishes the Poly1305 tag as the base64url `tag` header parameter (and asserts it is 16 bytes). `decryptKey()` requires the `tag` header, validates its length, and passes it to `openssl_decrypt()` so the tag is actually verified, in line with RFC 7539 / RFC 8439. Tampering now results in a decryption failure.\n\n\u003e Note: this changes the wire format of tokens produced with this experimental algorithm (a `tag` header is now emitted and required).\n\n### Workarounds\n\nDo not use the experimental `Chacha20Poly1305` key-encryption algorithm for untrusted input until upgraded.\n\n### References\n\n- RFC 7539 / RFC 8439 (ChaCha20-Poly1305 AEAD)\n- CWE-353: Missing Support for Integrity Check\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**ChaCha20-Poly1305** \u2014 le tag d\u0027authentification Poly1305 est d\u00e9sormais publi\u00e9 dans le header au chiffrement et v\u00e9rifi\u00e9 au d\u00e9chiffrement (RFC 7539), r\u00e9tablissant l\u0027int\u00e9grit\u00e9 AEAD.\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-6vvh-pxr4-25r7",
  "modified": "2026-06-18T21:08:15Z",
  "published": "2026-06-18T21:08:15Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/web-token/jwt-framework/security/advisories/GHSA-6vvh-pxr4-25r7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/web-token/jwt-library/GHSA-6vvh-pxr4-25r7.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/web-token/jwt-framework"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "PHP JWT Framework: Chacha20Poly1305 key-encryption algorithm discards the Poly1305 authentication tag, performing no authentication on decryption"
}