CVE-2026-44309— gitsign verify accepts signatures over go-git-normalized bytes, enabling trust confusion on malformed commits

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

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.

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

密码学签名的验证不恰当

Gitsign 信任管理问题漏洞

Gitsign是Gitsign个人开发者的一个能够免密钥完成对Git提交进行签名的工具。 Gitsign 0.16.0之前版本存在信任管理问题漏洞，该漏洞源于gitsign verify和gitsign verify-tag在检查签名前通过go-git的EncodeWithoutSignature重新编码提交/标签对象，而非验证原始git对象字节，对于具有重复树标头的畸形对象，git-core和go-git解析不同树，导致签名绕过验证而git-core解析为完全不同树，破坏验证签名、git-core呈现的

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