CVE-2026-48816: @sigstore/verify Sigstore-js Has Insufficient Verification Of Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xgjw-pm74-86q4",
  "modified" : "2026-07-01T19:57:45Z",
  "published" : "2026-07-01T19:57:45Z",
  "aliases" : [ "CVE-2026-48816" ],
  "summary" : "sigstore-js has Insufficient Verification of Data Authenticity",
  "details" : "sigstore-js derives a transparency-log timestamp from `tlogEntries[].integratedTime` and uses it to validate certificate validity windows and satisfy `timestampThreshold`. For bundle v0.2, a tlog entry can be inclusionProof-only (no signed inclusionPromise/set), and the inclusion proof path does not cryptographically bind `integratedTime`. As a result, an attacker who can supply an untrusted bundle can influence time-based verification decisions by choosing `integratedTime`.\n\n## impact\nIf a consumer accepts attacker-provided bundle v0.2 inputs and relies on tlog-derived timestamps for certificate validity checks, verification can be influenced by an unauthenticated timestamp value. This is a trust gap: `integratedTime` is treated as a trusted observer timestamp under inclusionProof-only mode even though only the signed inclusionPromise/set path binds it.\n\n## affected code\n- `packages/verify/src/bundle/index.ts` (adds a transparency-log timestamp whenever `integratedTime != 0`)\n- `packages/verify/src/timestamp/index.ts` (converts `integratedTime` to a `Date`)\n- `packages/verify/src/verifier.ts` (verifies timestamps before verifying tlog inclusion)\n- `packages/verify/src/tlog/index.ts` + `packages/verify/src/tlog/set.ts` (only the inclusionPromise/set path binds `integratedTime`)\n\n## proof of concept\nThe attached `poc.zip` contains a self-contained harness that reproduces the behavior on the pinned commit and includes both a canonical test and a negative control.\n\nrepro:\n1) extract `poc.zip` into a fresh directory and run the make targets:\n\n```bash\nunzip poc.zip -d poc\ncd poc/poc-F-SIG-JS-TLOGTIME-001\nmake canonical\nmake control\n```\n\n2) confirm `canonical.log` includes:\n\n```\n[CALLSITE_HIT]:\n[PROOF_MARKER]:\n```\n\n3) confirm `control.log` includes:\n\n```\n[NC_MARKER]:\n```\n\n## suggested fix\nOnly treat `integratedTime` as a trusted timestamp when it is cryptographically bound (for example, via a verified signed inclusionPromise/set). For inclusionProof-only entries, do not count `integratedTime` toward `timestampThreshold`, and do not use it for certificate validity decisions unless there is another signed time source (for example, an rfc3161 timestamp).\n\n[poc.zip](https://github.com/user-attachments/files/25643656/poc.zip)\n[PR_DESCRIPTION.md](https://github.com/user-attachments/files/25643660/PR_DESCRIPTION.md)\n[SUBMISSION.md](https://github.com/user-attachments/files/25643662/SUBMISSION.md)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@sigstore/verify"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.1.0"
      }, {
        "fixed" : "3.1.1"
      } ]
    } ],
    "versions" : [ "3.1.0" ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/sigstore/sigstore-js/security/advisories/GHSA-xgjw-pm74-86q4"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/sigstore/sigstore-js"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-345" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-01T19:57:45Z",
    "nvd_published_at" : null
  }
}