---
id: "CVE-2026-122318"
kind: "vulnerability"
aliases: ["CVE-2026-122318"]
title: "Kyverno: image signature check skips subject when certificate lacks SAN"
severity: "high"
cvss: 7.7
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["image-verification", "infrastructure", "kubernetes", "kyverno"]
not_affected_if: ["kyverno-1.19.2-or-later", "no-verifyimages", "public-trust-root-only"]
published_at: "2026-11-05T03:17:24+00:00"
first_seen_at: "2026-11-05T03:31:42+00:00"
updated_at: "2026-11-05T03:33:35+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-122318", "first_seen_at": "2026-11-05T03:31:42+00:00"}]
exploit_sources: []
---

# Kyverno: image signature check skips subject when certificate lacks SAN

Kyverno's verifyImages rule skips its subject and subjectRegExp checks when a signing certificate has no Subject Alternative Name. An attacker holding a leaf certificate from a configured private trust root can sign malicious images that are admitted despite signer pinning.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the Kyverno version running in the cluster, for example with `kubectl get deploy -n kyverno -o wide`, and compare it to `1.19.2`.
- Look for ClusterPolicy or Policy resources that use verifyImages with attestors or keys that rely on a private trust root and subject or subjectRegExp checks.

## Fix

- Kyverno: move to `1.19.2` or later.

## Timeline

- 2026-11-05T03:31:42+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-122318

## Documents

- [advisory] Vendor advisory: github.com https://github.com/kyverno/kyverno/security/advisories/GHSA-fcfr-fr8g-qjqv
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/kyverno-before-1.19.2-cosign-identity-check-bypass-via-empty-san-certificates

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_