Description
Kyverno before 1.19.2 contains an authentication bypass in matchCertificateData that skips verifyImages subject and subjectRegExp checks when the signing certificate has no Subject Alternative Name. Attackers holding a leaf certificate from a configured private trust root can omit the SAN, set the expected Fulcio issuer OID, and sign malicious images that are admitted despite signer pinning.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| kyverno | kyverno | < 1.19.2 | 1.19.2 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | kyverno-1.17 +1 | No fix yet | — |
Advisories 1
- WID-SEC-2026-4096 Kyverno: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 4, 2026
References
- GitHub Security Advisory (GHSA-fcfr-fr8g-qjqv) vendor-advisory
- VulnCheck Advisory: Kyverno before 1.19.2 Cosign Identity Check Bypass via Empty SAN Certificates third-party-advisory