CVE-2026-22703 Cosign verification accepts any valid Rekor entry under certain conditions

What is CVE-2026-22703?

CVE-2026-22703 is a medium-severity vulnerability in sigstore cosign, published on 10 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-345

Which versions are affected by CVE-2026-22703?

8 open source packages ship an affected version, including github.com/sigstore/cosign/v2, cosign and github.com/sigstore/cosign. It affects 1 product.

Products include Sigstore Cosign.

How do I fix CVE-2026-22703?

Upgrade github.com/sigstore/cosign/v2 to 2.6.2 or later.

Is CVE-2026-22703 being exploited?

There is no known exploitation of CVE-2026-22703 in the wild and no public exploit code.

Other vulnerabilities in sigstore cosign

• CVE-2022-35929 False positive signature verification in cosign High 7.1
• CVE-2022-36056 Vulnerabilities with blob verification in sigstore cosign Medium 5.5
• CVE-2026-39395 Cosign's verify-blob-attestation reports false positive when payload parsing fails Medium 4.3
• CVE-2024-29902 Cosign vulnerable to system-wide denial of service via malicious attachments Medium 4.2
• CVE-2024-29903 Cosign vulnerable to machine-wide denial of service via malicious artifacts Medium 4.2

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-cosign-2026-22703, CLEANSTART-2026-FC01276, CLEANSTART-2026-PA14127, DEBIAN-CVE-2026-22703, GHSA-whqx-f9j3-ch6m, GO-2026-4309 and 19 more.