{"id":"CVE-2026-44309","aliases":["GHSA-7rmh-48mx-2vwc","GO-2026-5233"],"url":"https://o3.security/vulnerability/CVE-2026-44309","summary":"gitsign verify accepts signatures over go-git-normalized bytes, enabling trust confusion on malformed commits","details":"Gitsign is a keyless Sigstore to signing tool for Git commits with your a GitHub / OIDC identity. Prior to 0.16.0, gitsign verify and gitsign verify-tag re-encode commit/tag objects through go-git's EncodeWithoutSignature before checking the signature, instead of verifying against the raw git object bytes. For malformed objects with duplicate tree headers, git-core and go-git parse different trees: git-core uses the first, go-git uses the second. A signature crafted over the go-git-normalized form (second tree) passes gitsign verify while git-core resolves the commit to a completely different tree. This breaks the invariant that a verified signature, the commit semantics git-core presents to users, and the object hash logged in Rekor all refer to the same content. This vulnerability is fixed in 0.16.0.","published":"2026-05-15T16:22:51.260Z","modified":"2026-08-12T03:51:30.267352336Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N"},"epss":{"score":0.00119,"percentile":0.01923,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/sigstore/gitsign","fixedVersion":"0.16.0"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44309.json"},{"type":"ADVISORY","url":"https://github.com/sigstore/gitsign/security/advisories/GHSA-7rmh-48mx-2vwc"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44309"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:30.267352336Z"}}