GHSA-w6c6-c85g-mmv6

Source

https://github.com/advisories/GHSA-w6c6-c85g-mmv6

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-w6c6-c85g-mmv6/GHSA-w6c6-c85g-mmv6.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-w6c6-c85g-mmv6

Aliases

BIT-cosign-2026-39395
CVE-2026-39395

Published

2026-04-08T00:15:44Z

Modified

2026-04-09T10:10:56.508139279Z

Severity

4.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N CVSS Calculator

Summary

Cosign's verify-blob-attestation reports false positive when payload parsing fails

Details

Description

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.

Impact

When cosign verify-blob-attestation is used without --check-claims set to true, an attestation that has a valid signature but a malformed or unparsable payload would be incorrectly validated. Additionally, systems relying on --type <predicate type> to reject attestations with mismatched types would be lead to trust the unexpected attestation type.

Patches

v3.0.6, v2.6.3

Workarounds

Always set --check-claims=true for attestation verification.

Database specific

{
    "nvd_published_at": "2026-04-07T20:16:33Z",
    "severity": "MODERATE",
    "github_reviewed": true,
    "cwe_ids": [
        "CWE-754"
    ],
    "github_reviewed_at": "2026-04-08T00:15:44Z"
}

References

Affected packages

Go / github.com/sigstore/cosign

Package

Name: github.com/sigstore/cosign; View open source insights on deps.dev
Purl: pkg:golang/github.com/sigstore/cosign

Affected ranges

Type: SEMVER
Events: Introduced

3.0.0

Fixed

3.0.6

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-w6c6-c85g-mmv6/GHSA-w6c6-c85g-mmv6.json"

Go / github.com/sigstore/cosign

Package

Name: github.com/sigstore/cosign; View open source insights on deps.dev
Purl: pkg:golang/github.com/sigstore/cosign

Affected ranges

Type: SEMVER
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

2.6.3

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-w6c6-c85g-mmv6/GHSA-w6c6-c85g-mmv6.json"