Vulnerability Details CVE-2026-39395
Cosign provides code signing and transparency for containers and binaries. Prior to 3.0.6 and 2.6.3, cosign verify-blob-attestation may erroneously report a "Verified OK" result for attestations with malformed payloads or mismatched predicate types. For old-format bundles and detached signatures, this was due to a logic flaw in the error handling of the predicate type validation. For new-format bundles, the predicate type validation was bypassed completely. This vulnerability is fixed in 3.0.6 and 2.6.3.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 8.9%
CVSS Severity
CVSS v3 Score 4.3
Products affected by CVE-2026-39395
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cpe:2.3:a:sigstore:cosign:-
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cpe:2.3:a:sigstore:cosign:0.1.0
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cpe:2.3:a:sigstore:cosign:0.2.0
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cpe:2.3:a:sigstore:cosign:0.3.0
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cpe:2.3:a:sigstore:cosign:0.3.1
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cpe:2.3:a:sigstore:cosign:0.4.0
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cpe:2.3:a:sigstore:cosign:0.5.0
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cpe:2.3:a:sigstore:cosign:0.6.0
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cpe:2.3:a:sigstore:cosign:1.0.0
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cpe:2.3:a:sigstore:cosign:1.0.1
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cpe:2.3:a:sigstore:cosign:1.1.0
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cpe:2.3:a:sigstore:cosign:1.10.0
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cpe:2.3:a:sigstore:cosign:1.10.1
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cpe:2.3:a:sigstore:cosign:1.11.0
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cpe:2.3:a:sigstore:cosign:1.11.1
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cpe:2.3:a:sigstore:cosign:1.12.0
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cpe:2.3:a:sigstore:cosign:1.12.1
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cpe:2.3:a:sigstore:cosign:1.13.0
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cpe:2.3:a:sigstore:cosign:1.13.1
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cpe:2.3:a:sigstore:cosign:1.2.0
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cpe:2.3:a:sigstore:cosign:1.2.1
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cpe:2.3:a:sigstore:cosign:1.3.0
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cpe:2.3:a:sigstore:cosign:1.3.1
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cpe:2.3:a:sigstore:cosign:1.4.0
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cpe:2.3:a:sigstore:cosign:1.4.1
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cpe:2.3:a:sigstore:cosign:1.5.0
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cpe:2.3:a:sigstore:cosign:1.5.1
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cpe:2.3:a:sigstore:cosign:1.5.2
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cpe:2.3:a:sigstore:cosign:1.6.0
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cpe:2.3:a:sigstore:cosign:1.7.0
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cpe:2.3:a:sigstore:cosign:1.7.1
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cpe:2.3:a:sigstore:cosign:1.7.2
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cpe:2.3:a:sigstore:cosign:1.8.0
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cpe:2.3:a:sigstore:cosign:1.9.0
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cpe:2.3:a:sigstore:cosign:2.0.0
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cpe:2.3:a:sigstore:cosign:2.0.1
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cpe:2.3:a:sigstore:cosign:2.0.2
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cpe:2.3:a:sigstore:cosign:2.1.0
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cpe:2.3:a:sigstore:cosign:2.1.1
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cpe:2.3:a:sigstore:cosign:2.2.0
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cpe:2.3:a:sigstore:cosign:2.2.1
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cpe:2.3:a:sigstore:cosign:2.2.2
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cpe:2.3:a:sigstore:cosign:2.2.3
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cpe:2.3:a:sigstore:cosign:2.2.4
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cpe:2.3:a:sigstore:cosign:2.3.0
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cpe:2.3:a:sigstore:cosign:2.4.0
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cpe:2.3:a:sigstore:cosign:2.4.1
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cpe:2.3:a:sigstore:cosign:2.4.2
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cpe:2.3:a:sigstore:cosign:2.4.3
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cpe:2.3:a:sigstore:cosign:2.5.0
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cpe:2.3:a:sigstore:cosign:2.5.1
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cpe:2.3:a:sigstore:cosign:2.5.2
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cpe:2.3:a:sigstore:cosign:2.5.3
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cpe:2.3:a:sigstore:cosign:2.6.0
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cpe:2.3:a:sigstore:cosign:2.6.1
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cpe:2.3:a:sigstore:cosign:2.6.2
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cpe:2.3:a:sigstore:cosign:3.0.0
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cpe:2.3:a:sigstore:cosign:3.0.1
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cpe:2.3:a:sigstore:cosign:3.0.2
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cpe:2.3:a:sigstore:cosign:3.0.3
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cpe:2.3:a:sigstore:cosign:3.0.4