Description
Kyverno before 1.19.2 contains a denial of service vulnerability in substituteVariablesIfAny that allows low-privileged users to hang the admission webhook via self-referential variable templates. Attackers can create resources whose annotations re-introduce the embedded policy variable, causing unbounded substitution loops that exhaust CPU and memory and block cluster-wide admission.
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-338x-hgrv-626h) vendor-advisory
- VulnCheck Advisory: Kyverno before 1.19.2 Denial of Service via Nested Variable Substitution Loop third-party-advisory