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.
History

Wed, 14 Jan 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Mon, 12 Jan 2026 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 12 Jan 2026 14:45:00 +0000

Type Values Removed Values Added
First Time appeared Sigstore
Sigstore cosign
Vendors & Products Sigstore
Sigstore cosign

Sat, 10 Jan 2026 06:30:00 +0000

Type Values Removed Values Added
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.
Title Cosign verification accepts any valid Rekor entry under certain conditions
Weaknesses CWE-345
References
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-01-10T06:11:09.426Z

Updated: 2026-01-12T16:43:57.302Z

Reserved: 2026-01-08T19:23:09.857Z

Link: CVE-2026-22703

cve-icon Vulnrichment

Updated: 2026-01-12T16:43:54.654Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-01-10T07:16:03.030

Modified: 2026-01-13T14:03:18.990

Link: CVE-2026-22703

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-01-10T06:11:09Z

Links: CVE-2026-22703 - Bugzilla