[github.com/sigstore/policy-controller] PolicyController before 0.2.1 may bypass attestation verification

PolicyController will report a false positive, resulting in an admission when it should not be admitted when:

• There is at least one attestation with a valid signature
• There are NO attestations of the type being verified (–type defaults to “custom”)

Users should upgrade to cosign version 0.2.1 or greater for a patch. There are no known workarounds at this time.

References

• https://github.com/sigstore/policy-controller/security/advisories/GHSA-739f-hw6h-7wq8
• https://nvd.nist.gov/vuln/detail/CVE-2022-35930
• https://github.com/sigstore/policy-controller/commit/e852af36fb7d42678b21d7e97503c25bd1fd05c8
• https://github.com/sigstore/policy-controller/releases/tag/v0.2.1
• https://github.com/advisories/GHSA-739f-hw6h-7wq8