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.
History

Fri, 15 May 2026 18:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 15 May 2026 17:45:00 +0000

Type Values Removed Values Added
First Time appeared Sigstore
Sigstore gitsign
Vendors & Products Sigstore
Sigstore gitsign

Fri, 15 May 2026 16:45:00 +0000

Type Values Removed Values Added
Description 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.
Title gitsign verify accepts signatures over go-git-normalized bytes, enabling trust confusion on malformed commits
Weaknesses CWE-295
CWE-347
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-15T17:43:59.446Z

Reserved: 2026-05-05T19:00:06.021Z

Link: CVE-2026-44309

cve-icon Vulnrichment

Updated: 2026-05-15T17:42:44.620Z

cve-icon NVD

Status : Received

Published: 2026-05-15T17:16:47.297

Modified: 2026-05-15T18:16:25.703

Link: CVE-2026-44309

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-15T17:30:04Z