eef-cve-2026-65632

{
  "affected": [
    {
      "database_specific": {
        "source": "https://cna.erlef.org/osv/EEF-CVE-2026-65632.json"
      },
      "package": {
        "ecosystem": "Hex",
        "name": "jose",
        "purl": "pkg:hex/jose"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.0.0"
            },
            {
              "fixed": "1.11.13"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": [
        "1.0.0",
        "1.0.1",
        "1.1.0",
        "1.1.1",
        "1.1.2",
        "1.1.3",
        "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-2026-65632.json"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "a7746ecd4950f85a393136e449a91dac62b5c429"
            },
            {
              "fixed": "72ce1866622b9329347dc52a94173ac0317bc9cf"
            }
          ],
          "repo": "https://github.com/potatosalad/erlang-jose",
          "type": "GIT"
        }
      ],
      "versions": [
        "1.11.12",
        "1.11.11",
        "1.11.10",
        "1.11.9",
        "1.11.8",
        "1.11.7",
        "1.11.5",
        "1.11.4",
        "1.11.2",
        "1.11.1",
        "1.11.0",
        "1.10.1",
        "1.10.0",
        "1.9.0",
        "1.8.4",
        "1.8.3",
        "1.8.2",
        "1.8.1",
        "1.8.0",
        "1.7.9",
        "1.7.8",
        "1.7.7",
        "1.7.6",
        "1.7.5",
        "1.7.4",
        "1.7.3",
        "1.7.2",
        "1.7.1",
        "1.7.0",
        "1.6.1",
        "1.6.0",
        "1.5.2",
        "1.5.1",
        "1.5.0",
        "1.4.2",
        "1.4.1",
        "1.4.0",
        "1.3.0",
        "1.2.0",
        "1.1.3",
        "1.1.2",
        "1.1.1",
        "1.1.0",
        "1.0.1",
        "1.0.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-65632",
    "GHSA-44hw-rpw9-mwg4"
  ],
  "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-347"
    ]
  },
  "details": "## Summary\n\nThe `jose` library accepts ECDSA (ES256, ES256K, ES384, and ES512) JWS signatures of a non-canonical length. When verifying an ECDSA signature, `jose_jwk_kty_ec:verify/4` in `src/jwk/jose_jwk_kty_ec.erl` splits the raw signature in half by its actual byte length (`split_binary(Signature, byte_size(Signature) div 2)`) instead of enforcing the fixed length required by RFC 7518 §3.4, and then decodes each half with `crypto:bytes_to_integer/1`, which ignores leading zero bytes.\n\nAs a result, an attacker who holds one valid token can prepend leading zero bytes to each of the R and S halves to produce longer signatures that still split evenly and decode to the same `(r, s)` pair, so many distinct signature byte strings all verify against the same key (signature malleability). This does not allow forging new payloads or impersonating a signer, because the underlying `(r, s)` values are unchanged. It does defeat any security control that assumes a valid token or its signature is unique, such as token-revocation-by-hash, replay or idempotency caches, and deduplication logic.\n\nThis issue affects jose: from 1.0.0 before 1.11.13.",
  "id": "EEF-CVE-2026-65632",
  "modified": "2026-10-26T20:11:07.849428784Z",
  "published": "2026-10-26T19:53:56.649Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-44hw-rpw9-mwg4"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-65632.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/potatosalad/erlang-jose/commit/a7746ecd4950f85a393136e449a91dac62b5c429"
    },
    {
      "type": "FIX",
      "url": "https://github.com/potatosalad/erlang-jose/commit/72ce1866622b9329347dc52a94173ac0317bc9cf"
    },
    {
      "type": "PACKAGE",
      "url": "https://hex.pm/packages/jose"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "ECDSA signature length is not validated in jose, allowing signature malleability"
}