# CVE-2026-122306: Kyverno denial of service via wildcard matching

Source: https://junglewise.ai/threats/cve-2026-122306-kyverno-before-1-19-2-contains-a-denial-of-service-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-05. Updated: 2026-11-05  
License: CC BY 4.0 with a link back

CVE-2026-122306 · Severity: high · CVSS 7.7 · Published 2026-11-05

Kyverno is a policy engine for Kubernetes clusters that validates and enforces resource configurations. A denial of service vulnerability allows users with policy creation permissions to craft malicious patterns that cause the admission controller to consume CPU excessively, potentially blocking all resource operations cluster-wide. An attacker can pin CPU cores and trigger webhook timeouts that prevent legitimate Kubernetes operations from completing.

Technologies: [Kyverno](https://junglewise.ai/threats/technologies/kyverno). Vendors: [Kyverno](https://junglewise.ai/threats/vendors/kyverno).

## Quick answers

**Is CVE-2026-122306 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-122306 being exploited in the wild.

**How severe is CVE-2026-122306?** High severity, with a CVSS score of 7.7, published 5 November 2026.

**Which products and versions are affected?** Kyverno before 1.19.2.

**Is there a fix for CVE-2026-122306?** Yes: fixed in 1.19.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-122306 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-122306?** Check whether you run Kyverno at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.19.2

## Technical details

The vulnerability exists in Kyverno's wildcard matching implementation (via the pinned go-wildcard v1.0.3 library), which uses recursive backtracking with exponential worst-case complexity. A namespaced policy author can trigger the issue during policy admission by submitting a Policy with crafted match and exclude resource names in the ValidateMatchExcludeConflict validation path, or during resource admission through pattern matching against user-controlled fields. The goroutine performing the match ignores request deadlines and continues spinning even after timeouts, causing cluster-wide webhook failures with failurePolicy: Fail.

## Affected products

- Kyverno Kyverno before 1.19.2

## Timeline

- 2026-10-21: disclosed
- 2026-11-05: advisory

## References

- [https://github.com/kyverno/kyverno/security/advisories/GHSA-8mrj-27wr-599g](https://github.com/kyverno/kyverno/security/advisories/GHSA-8mrj-27wr-599g)
- [https://www.vulncheck.com/advisories/kyverno-before-1.19.2-denial-of-service-via-exponential-time-wildcard-matching](https://www.vulncheck.com/advisories/kyverno-before-1.19.2-denial-of-service-via-exponential-time-wildcard-matching)

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