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CVE-2026-44309

gitsign verify accepts signatures over go-git-normalized bytes, enabling trust confusion on malformed commits PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
sigstore / gitsignaffected < 0.16.0

CWE

CWE-347, CWE-295

References

ADP enrichment

CISA-ADP

No English description supplied.