Vulnerability CVE-2026-39395: Information
Description
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.
Severity: MEDIUM (4.3)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Fixed packages
Package name | Branch | Fixed in version | Version from repository | Errata ID | Task # | State |
|---|---|---|---|---|---|---|
| cosign | sisyphus | 3.0.6-alt1 | 3.0.6-alt1 | ALT-PU-2026-5932-2 | 414543 | Fixed |
| cosign | sisyphus_riscv64 | 3.0.6-alt1 | 3.0.6-alt1 | ALT-PU-2026-6061-1 | - | Fixed |
| cosign | sisyphus_loongarch64 | 3.0.6-alt1 | 3.0.6-alt1 | ALT-PU-2026-5997-1 | - | Fixed |
| cosign | p11 | 3.0.6-alt1 | 3.0.6-alt1 | ALT-PU-2026-5940-2 | 414548 | Fixed |
| cosign | c10f2 | 3.0.6-alt1 | 3.0.6-alt1 | ALT-PU-2026-5938-2 | 414547 | Fixed |