{"id":"CVE-2026-54787","aliases":["GHSA-wqqc-jjcq-vfxm","GO-2026-6162"],"url":"https://o3.security/vulnerability/CVE-2026-54787","summary":"sigstore-go fails to check signature timestamps against a signing key's validity period","details":"sigstore-go is a Go library for Sigstore signing and verification. Prior to 1.2.1, sigstore-go does not check a bundle signing timestamp against the validity window of an ExpiringKey wrapping a self-managed long-lived signing key without a certificate, which can allow an attacker holding expired key material to sign accepted bundles. This issue is fixed in version 1.2.1.","published":"2026-07-31T21:58:14.156Z","modified":"2026-09-12T03:30:51.228134298Z","cvss":{"score":3.1,"severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N"},"epss":{"score":0.0009,"percentile":0.00527,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/sigstore/sigstore-go","fixedVersion":"1.2.1"}],"fix":{"url":"https://github.com/sigstore/sigstore-go/commit/4594ab4c779d08be1f4419803a8249188f35ed5f","label":"sigstore/sigstore-go@4594ab4"},"references":[{"type":"WEB","url":"https://github.com/sigstore/sigstore-go/releases/tag/v1.2.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54787.json"},{"type":"ADVISORY","url":"https://github.com/sigstore/sigstore-go/security/advisories/GHSA-wqqc-jjcq-vfxm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54787"},{"type":"FIX","url":"https://github.com/sigstore/sigstore-go/commit/4594ab4c779d08be1f4419803a8249188f35ed5f"},{"type":"FIX","url":"https://github.com/sigstore/sigstore-go/pull/642"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-12T03:30:51.228134298Z"}}