{"id":"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.","aliases":["GHSA-7rmh-48mx-2vwc","GO-2026-5233"],"modified":"2026-07-15T01:49:11.116929957Z","published":"2026-05-15T16:22:51.260Z","related":["CGA-3ccp-gf5g-46gp"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-295","CWE-347"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44309.json"},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/sigstore/gitsign","events":[{"introduced":"0"},{"fixed":"3c84d87240644b5c62b3b3d79177ae64448591c8"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"0"},{"fixed":"0.16.0"}]}}],"versions":["v0.15.1","v0.15.0","v0.14.0","v0.13.0","v0.12.0","v0.11.0","v0.10.2","v0.10.1","v0.9.1","v0.10.0","v0.9.0","v0.8.1","v0.8.0","v0.7.1","v0.7.0","v0.6.0","v0.5.2","v0.5.1","v0.5.0","v0.4.1","v0.4.0","v0.3.2","v0.3.1","v0.3.0","v0.2.0","v0.1.1","v0.1.0","v0.0.2-alpha","v0.0.1-alpha","v0.0.0-test"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44309.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N"}]}