# CVE-2026-124440: Kyverno apiCall authorization bypass in namespace clamp

Source: https://junglewise.ai/threats/cve-2026-124440-kyverno-from-1-19-1-before-1-19-2-contains-an-authorization  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-08. Updated: 2026-11-08  
License: CC BY 4.0 with a link back

CVE-2026-124440 · Severity: critical · CVSS 9.9 · Published 2026-11-08

Kyverno is a policy engine for Kubernetes clusters that validates and mutates workload configurations. In version 1.19.1, a namespace tenant can bypass authorization controls by crafting malformed API requests, allowing them to read secrets and resources from other namespaces and create cluster-admin webhooks. This enables complete cluster compromise from a user with minimal initial privileges.

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

## Quick answers

**Is CVE-2026-124440 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-124440 being exploited in the wild.

**How severe is CVE-2026-124440?** Critical severity, with a CVSS score of 9.9, published 8 November 2026.

**Which products and versions are affected?** Kyverno 1.19.1.

**Is there a fix for CVE-2026-124440?** 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-2026-124440 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-124440?** 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 is an authorization bypass in the apiCall namespace clamp introduced in v1.19.1. The clamp validates a decoded and cleaned path (url.PathUnescape and path.Clean) but issues the actual request against the raw, unmodified urlPath. By appending a malformed percent-escape such as ?a=% to the urlPath, an attacker forces url.PathUnescape to fail, causing the clamp to validate one path while the Kubernetes API server routes the request to a different namespace or cluster-scoped resource. The apiCall runs as the admission-controller ServiceAccount, allowing the attacker to read arbitrary namespaces and create mutating webhooks for cluster-admin escalation.

## Affected products

- Kyverno Kyverno 1.19.1

## Timeline

- 2026-10-23: disclosed
- 2026-11-08: advisory

## References

- [https://github.com/kyverno/kyverno/security/advisories/GHSA-39w8-hv5g-f73w](https://github.com/kyverno/kyverno/security/advisories/GHSA-39w8-hv5g-f73w)
- [https://www.vulncheck.com/advisories/kyverno-1.19.1-privilege-escalation-via-apicall-namespace-clamp-bypass](https://www.vulncheck.com/advisories/kyverno-1.19.1-privilege-escalation-via-apicall-namespace-clamp-bypass)

## Related threats

- [Kyverno authorization bypass in generate rule validation](https://junglewise.ai/threats/cve-2026-124441-kyverno-before-1-19-2-contains-an-authorization-bypass)
- [Kyverno unbounded decompression in notary signature fetch](https://junglewise.ai/threats/cve-2026-122323-kyverno-from-1-11-0-before-1-19-2-contains-an-unbounded)
- [Kyverno verifyImages signature verification bypass via cache](https://junglewise.ai/threats/cve-2026-122321-kyverno-1-18-0-before-1-19-2-contains-a-signature-verification)
- [Kyverno missing authorization in generate.clone namespace](https://junglewise.ai/threats/cve-2026-122320-kyverno-before-1-19-2-contains-a-missing-authorization)
- [Kyverno denial-of-service in In and NotIn operators](https://junglewise.ai/threats/cve-2026-122319-kyverno-before-1-19-2-contains-a-denial-of-service-vulnerability)