---
id: "CVE-2026-124440"
page: "https://infrastack.ai/live/CVE-2026-124440"
kind: "vulnerability"
aliases: ["CVE-2026-124440"]
title: "Kyverno: namespace tenants can escalate to cluster admin via apiCall"
severity: "critical"
cvss: 9.9
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "kubernetes", "kyverno", "self-hosted"]
not_affected_if: ["kyverno-not-1.19.1", "no-tenant-policy-writes"]
published_at: "2026-11-08T14:18:10+00:00"
first_seen_at: "2026-11-08T14:48:39+00:00"
updated_at: "2026-11-08T14:48:46+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-124440", "first_seen_at": "2026-11-08T14:48:39+00:00"}]
exploit_sources: []
---

# Kyverno: namespace tenants can escalate to cluster admin via apiCall

Link for people: https://infrastack.ai/live/CVE-2026-124440 (this .md is for agents)

Kyverno 1.19.1 before 1.19.2 lets a namespace tenant bypass the namespace restriction on apiCall by appending malformed percent-escapes to urlPath. An attacker with a namespaced Policy can make requests as the admission-controller ServiceAccount, reading other namespaces' resources and creating mutating webhooks to reach cluster admin.

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

## How to check

- Check the installed Kyverno version, for example with `kubectl get deploy -n kyverno -o jsonpath='{.items[*].spec.template.spec.containers[*].image}'`
- Confirm whether tenants can create Policies in their own namespaces, since that is the required access
- Review existing Policies that use apiCall for unusual urlPath values containing percent-escapes

## Fix

- Kyverno: move to `1.19.2` or later (the sources state 1.19.2 is the fixed version)

## Timeline

- 2026-11-08T14:48:39+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-124440

## Documents

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

## From the sources

Kyverno from 1.19.1 before 1.19.2 contains an authorization bypass vulnerability in the apiCall namespace clamp that allows namespace tenants to issue cross-namespace and cluster-scoped API requests by appending malformed percent-escapes to urlPath. Attackers can create namespaced Policies whose apiCall runs as the admission-controller ServiceAccount to read other namespaces' resources and create mutating webhooks, escalating to cluster admin.

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