{
  "affected": [
    {
      "database_specific": {
        "source": "https://cna.erlef.org/osv/EEF-CVE-2026-65625.json"
      },
      "package": {
        "ecosystem": "Hex",
        "name": "jose",
        "purl": "pkg:hex/jose"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.2.0"
            },
            {
              "fixed": "1.11.13"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": [
        "1.10.0",
        "1.10.1",
        "1.11.0",
        "1.11.1",
        "1.11.10",
        "1.11.11",
        "1.11.12",
        "1.11.2",
        "1.11.4",
        "1.11.5",
        "1.11.6",
        "1.11.7",
        "1.11.8",
        "1.11.9",
        "1.2.0",
        "1.3.0",
        "1.4.0",
        "1.4.1",
        "1.4.2",
        "1.5.0",
        "1.5.1",
        "1.5.2",
        "1.6.0",
        "1.6.1",
        "1.7.0",
        "1.7.1",
        "1.7.2",
        "1.7.3",
        "1.7.4",
        "1.7.5",
        "1.7.6",
        "1.7.7",
        "1.7.8",
        "1.7.9",
        "1.8.0",
        "1.8.1",
        "1.8.2",
        "1.8.3",
        "1.8.4",
        "1.9.0"
      ]
    },
    {
      "database_specific": {
        "source": "https://cna.erlef.org/osv/EEF-CVE-2026-65625.json"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8848b172575fb7d7e1e2977e8ae0a21678d2157a"
            },
            {
              "fixed": "3fa1f8e3efda0da5ce6f4c9984789f979dc02740"
            }
          ],
          "repo": "https://github.com/potatosalad/erlang-jose",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-65625",
    "GHSA-6gxw-6f7r-cjr6"
  ],
  "credits": [
    {
      "name": "Peter Ullrich",
      "type": "REPORTER"
    },
    {
      "name": "Andrew Bennett",
      "type": "REMEDIATION_DEVELOPER"
    },
    {
      "name": "Jonatan Männchen / EEF",
      "type": "ANALYST"
    }
  ],
  "database_specific": {
    "capec_ids": [
      "CAPEC-475"
    ],
    "cpe_ids": [
      "cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:*"
    ],
    "cwe_ids": [
      "CWE-354"
    ]
  },
  "details": "## Summary\n\nThe pure-Erlang AES-GCM fallback in `jose_jwa_aes` derives the number of verified authentication tag bits from the attacker-supplied tag itself. In the `{aes_gcm, Bits}` clause of `block_decrypt/4`, the incoming tag is guarded only by `is_binary/1`, with no check on its length. Verification in `gcm_block_decrypt/6` then computes `TBits = bit_size(T)` and compares only those bits of the real 128-bit tag. An attacker who controls a JWE token can truncate the authentication tag to as little as 8 bits, so only 8 bits are ever checked. This reduces forgery resistance from 2^-128 to 2^-8, and a forged ciphertext is reliably accepted as authentic within 256 attempts without knowledge of the key (an authentication tag forgery and integrity bypass). Supplying a tag longer than 128 bits instead causes a badmatch that crashes the decrypting process. The fallback is reached through the public JWE decryption path whenever AES-GCM is not provided by a native crypto NIF, for example on FIPS or stripped or older OTP builds.\n\nThis issue affects jose: from 1.2.0 before 1.11.13.\n\n## Workarounds\n\nEnsure the runtime provides a crypto provider with native AES-GCM support (a standard Erlang/OTP build linked against OpenSSL) so that JOSE dispatches AES-GCM to the native `crypto` NIF instead of the `jose_jwa_aes` fallback.\n\n## Configurations\n\nThis vulnerability is only exploitable when AES-GCM is handled by the pure-Erlang `jose_jwa_aes` fallback. That fallback is used on deployments where the Erlang/OTP `crypto` NIF does not expose native AES-GCM (for example FIPS builds, or stripped or older OTP releases). Deployments with a native AES-GCM crypto provider dispatch GCM through `crypto` and are not affected.",
  "id": "EEF-CVE-2026-65625",
  "modified": "2026-10-26T20:11:07.497402732Z",
  "published": "2026-10-26T19:52:54.987Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-6gxw-6f7r-cjr6"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-65625.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/potatosalad/erlang-jose/commit/8848b172575fb7d7e1e2977e8ae0a21678d2157a"
    },
    {
      "type": "FIX",
      "url": "https://github.com/potatosalad/erlang-jose/commit/3fa1f8e3efda0da5ce6f4c9984789f979dc02740"
    },
    {
      "type": "PACKAGE",
      "url": "https://hex.pm/packages/jose"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Attacker-controlled AES-GCM authentication tag length allows tag forgery in jose"
}