Is CVE-2026-39395 actively exploited?

CVE-2026-39395 has no public evidence of in-the-wild exploitation as of 2026-04-15.

What is the CVSS score for CVE-2026-39395?

CVE-2026-39395 has a CVSS score of 4.3 (MEDIUM severity). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.

How do I patch CVE-2026-39395?

Patch guidance is available from sigstore security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-39395.

Which products are affected by CVE-2026-39395?

2 products: sigstore cosign, sigstore cosign.

CVE-2026-39395 - remediation guidance & executive summary

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.

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Attack Vector: network
Complexity: low
Privileges: none
User Action: required
Scope: unchanged
Confidentiality: none
Integrity: low
Availability: none
Weaknesses: CWE-754

Metadata

Primary Vendor: SIGSTORE
Published: 4/7/2026
Last Modified: 4/15/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

CVE-2026-39395

Description

CVSS Metrics

Metadata

Affected Products

Remediation Guidance

Executive Summary