Vulnerability in github.com/sigstore/gitsign (CVE-2026-44309)
Summary
Vulnerability in github.com/sigstore/gitsign (CVE-2026-44309). Data can be tampered with by attackers. Exploitable via EncodeWithoutSignature. Mitigation: upgrade to 0.16.0 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-44309 has been found in github.com/sigstore/gitsign.
Attackers can target a specific entry point like EncodeWithoutSignature over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 5.3/10.
What to do: upgrade github.com/sigstore/gitsign to 0.16.0 or later.
If unsure, ask your IT team or search "github.com/sigstore/gitsign CVE-2026-44309" on the vendor's site.
CVE-2026-44309 (github.com/sigstore/gitsign) — CWE-295 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: EncodeWithoutSignature / tree / ObjectHash / commandVerify
Patched: 0.16.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-295) exists in github.com/sigstore/gitsign. Attackers reach the vulnerable code path via EncodeWithoutSignature without authentication.
Check the vendor advisory for the affected versions of github.com/sigstore/gitsign. Attack surface: EncodeWithoutSignature / tree / ObjectHash / commandVerify.
Severity: Medium (CVSS 5.3/10). Data can be tampered with by attackers.
Update to 0.16.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/sigstore/gitsign' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/sigstore/gitsign' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/sigstore/gitsignを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/sigstore/gitsign to 0.16.0ステージング環境で 0.16.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-44309 gitsign
- Ubuntu UBUNTU-CVE-2026-44309 gitsign
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com