Bug 2456254 (CVE-2026-39395) - CVE-2026-39395 github.com/sigstore/cosign: Cosign: Incorrect attestation verification due to malformed payloads or mismatched predicate types
Summary: CVE-2026-39395 github.com/sigstore/cosign: Cosign: Incorrect attestation veri...
Keywords:
Status: NEW
Alias: CVE-2026-39395
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2456377 2456378 2456379 2456380
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-07 21:01 UTC by OSIDB Bzimport
Modified: 2026-04-08 08:56 UTC (History)
19 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)

Description OSIDB Bzimport 2026-04-07 21:01:55 UTC 
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.
Note You need to log in before you can comment on or make changes to this bug.