{"id":"UBUNTU-CVE-2026-44309","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.","modified":"2026-07-02T18:03:13.926532447Z","published":"2026-05-15T17:16:00Z","upstream":["CVE-2026-44309"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-44309"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-44309"},{"type":"REPORT","url":"https://github.com/sigstore/gitsign/security/advisories/GHSA-7rmh-48mx-2vwc"}],"affected":[{"package":{"name":"gitsign","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/gitsign?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.12.0-4","0.13.0-1","0.13.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"gitsign","binary_version":"0.13.0-2"},{"binary_version":"0.13.0-2","binary_name":"golang-github-sigstore-gitsign-dev"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44309.json"}},{"package":{"name":"gitsign","ecosystem":"Ubuntu:Pro:26.04:LTS","purl":"pkg:deb/ubuntu/gitsign?arch=source&distro=esm-apps%2Fresolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.13.0-2","0.13.0-3","0.13.0-4","0.13.0-4ubuntu0.26.04.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"gitsign","binary_version":"0.13.0-4ubuntu0.26.04.1~esm1"},{"binary_version":"0.13.0-4ubuntu0.26.04.1~esm1","binary_name":"golang-github-sigstore-gitsign-dev"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-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"},{"type":"Ubuntu","score":"medium"}]}