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Improper Verification of Cryptographic Signature


Severity High
Score 9.8/10


cosign is a container signing and verification utility. In versions prior to 1.10.1 cosign can report a false positive if any attestation exists. `cosign verify-attestation` used with the `--type` flag will report a false positive verification when there is at least one attestation with a valid signature and there are NO attestations of the type being verified (--type defaults to "custom"). This can happen when signing with a standard keypair and with "keyless" signing with Fulcio. This vulnerability can be reproduced with the `` image. This image has a `vuln` attestation but not an `spdx` attestation. However, if you run `cosign verify-attestation --type=spdx` on this image, it incorrectly succeeds. This issue has been addressed in version 1.10.1 of cosign. Users are advised to upgrade. There are no known workarounds for this issue.

  • LOW
  • HIGH
  • NONE
  • NONE
  • HIGH
  • HIGH

CWE-347 - Improper Verification of Cryptographic Signature

A cryptographic protocol is meant to ensure that services are provided in a secure manner. An application with absent or improper verification of cryptographic signatures allows malicious users to feed false messages to valid users or to disclose sensitive data, subverting the goals of the protocol. This can lead to security failures such as false authentication, account hijacking, and privilege escalation.

Advisory Timeline

  • Published