{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/google/go-attestation"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "0.5.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-20"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-12T15:04:43Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\n`parseEfiSignatureList()` in `attest/internal/events.go` does not skip `SignatureHeaderSize` vendor bytes before reading `EFI_SIGNATURE_LIST` signature entries, violating UEFI specification section 31.4.1.\n\n## Impact\n\nFor `hashSHA256SigGUID` lists, attacker-controlled vendor header bytes are appended directly to the trusted SHA256 hash list. A crafted TPM event log can inject arbitrary SHA256 hashes into the verifier\u0027s trusted measurement database, allowing a remote attestation verifier to accept a compromised boot state as legitimate \u2014 breaking the core integrity guarantee of remote attestation.\n\n## Root Cause\n\nAfter `binary.Read(\u0026signatures.Header)` reads 28 bytes, `buf` points to the start of the `SignatureHeaderSize` vendor bytes. Both entry loops start at `sigOffset := 0` instead of `sigOffset := SignatureHeaderSize`, causing vendor bytes to be read as signature entries.\n\n## Affected versions\n\nAll versions through commit `f877374` (2026-05-15).\n\n## Fix\n\nPull request: https://github.com/google/go-attestation/pull/502\n\n- Add bound check: `SignatureHeaderSize` must not exceed remaining list space\n- Skip `SignatureHeaderSize` bytes before both entry loops\n- Regression test: `TestParseEfiSignatureListNonZeroSignatureHeaderSize`",
  "id": "GHSA-9r4w-jg96-92mv",
  "modified": "2026-06-12T15:04:43Z",
  "published": "2026-06-12T15:04:43Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/google/go-attestation/security/advisories/GHSA-9r4w-jg96-92mv"
    },
    {
      "type": "WEB",
      "url": "https://github.com/google/go-attestation/pull/502"
    },
    {
      "type": "WEB",
      "url": "https://github.com/google/go-attestation/commit/b6e905e7ae52937f02b5ca494dd1c6a3ac7a1003"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/google/go-attestation"
    },
    {
      "type": "WEB",
      "url": "https://github.com/google/go-attestation/releases/tag/v0.6.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Go-Attestation: Hash injection into trusted measurement list via unskipped SignatureHeaderSize vendor bytes in parseEfiSignatureList()"
}