{"schema_version":"1.7.5","id":"GHSA-9vcr-p3rj-q5q6","published":"2026-07-09T23:20:30Z","modified":"2026-07-31T20:30:21.954042356Z","aliases":["CVE-2026-49834","GO-2026-5952"],"related":["CGA-2j38-cxfp-c8p6"],"summary":"sigstore-go has a multi-log threshold bypass via single compromised log","details":"### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\nA verifier configured with WithTransparencyLog(N>1) or WithSignedCertificateTimestamps(N>1) expected defense-in-depth against the compromise of a single log instance. However, threshold counting counted verified witnesses per-entry or per-validation-path rather than per-log-authority.\n\nAs a result, a single compromised transparency log could forge multiple entries with different indices, and a single compromised CT log could verify multiple times (either across multiple certificate chains or via multiple embedded SCTs), fully satisfying the multi-log threshold requirements and defeating the multi-log policy.\n\nNote that this does not affect Cosign, as Cosign sets a threshold of 1.\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\n\nUpgrade to v1.1.5.\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\n\nThere is no workaround, beyond relying on trusted logs.","affected":[{"package":{"name":"github.com/sigstore/sigstore-go","ecosystem":"Go","purl":"pkg:golang/github.com/sigstore/sigstore-go"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.2.0"}]}],"database_specific":{"last_known_affected_version_range":"<= 1.1.4","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-9vcr-p3rj-q5q6/GHSA-9vcr-p3rj-q5q6.json"}}],"references":[{"type":"WEB","url":"https://github.com/sigstore/sigstore-go/security/advisories/GHSA-9vcr-p3rj-q5q6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-49834"},{"type":"WEB","url":"https://github.com/sigstore/sigstore-go/pull/633"},{"type":"WEB","url":"https://github.com/sigstore/sigstore-go/commit/dbb07e62623edd5b175fb9dd5a41dcb85a159207"},{"type":"PACKAGE","url":"https://github.com/sigstore/sigstore-go"},{"type":"WEB","url":"https://github.com/sigstore/sigstore-go/releases/tag/v1.2.0"}],"database_specific":{"cwe_ids":["CWE-345","CWE-347"],"github_reviewed":true,"github_reviewed_at":"2026-07-09T23:20:30Z","nvd_published_at":"2026-07-17T20:17:21Z","severity":"MODERATE"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}