Vulnerability in github.com/sigstore/cosign (CVE-2026-22703)
Summary
Vulnerability in github.com/sigstore/cosign (CVE-2026-22703). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 2.6.2 or later.
Original description
The description as published by the source.
Cosign provides code signing and transparency for containers and binaries. Prior to versions 2.6.2 and 3.0.4, Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact's digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact's digest, the user's public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user's identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This issue has been patched in versions 2.6.2 and 3.0.4.
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
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-2026-22703 has been found in github.com/sigstore/cosign.
Risk of unauthorized operations or information disclosure.
What to do: upgrade github.com/sigstore/cosign to 2.6.2 or later.
If unsure, ask your IT team or search "github.com/sigstore/cosign CVE-2026-22703" on the vendor's site.
CVE-2026-22703 (github.com/sigstore/cosign)
Patched: 2.6.2 — 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 (unclassified) exists in github.com/sigstore/cosign.
Check the vendor advisory for the affected versions of github.com/sigstore/cosign.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 2.6.2.
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/cosign' . 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/cosign' . | 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/cosign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/cosign to 2.6.2ステージング環境で 2.6.2 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-2026-22703 cosign
- Ubuntu UBUNTU-CVE-2026-22703 cosign
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- patch github.com
- patch github.com