Insufficient verification of data authenticity in Cosign - CVE-2026-22703
Published: April 25, 2026
Vulnerability identifier: #VU127931
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-22703
CWE-ID: CWE-345
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Sigstore
Affected software:
Cosign
Cosign
Detailed vulnerability description
The vulnerability allows a local user to cause acceptance of an invalid signing bundle.
The vulnerability exists due to insufficient verification of data authenticity in Rekor entry verification when verifying a crafted Cosign bundle. A local user can include an arbitrary valid Rekor entry in the bundle to cause acceptance of an invalid signing bundle.
This only affects verification when a trusted root is provided via --trusted-root or fetched automatically from a TUF repository and no trusted key material is provided via SIGSTORE_REKOR_PUBLIC_KEY.
How to mitigate CVE-2026-22703
Install security update from vendor's website.