CVE-2026-54523 — Kyverno is a policy engine designed for cloud native platform engineering teams.¶
Key facts
CVE-2026-54523 is a Critical (9.6) vulnerability: Kyverno is a policy engine designed for cloud native platform engineering teams.. This entry ships a detection-only PoC and a Docker test lab.
| CVE | CVE-2026-54523 |
| Severity | Critical (9.6) |
| Detection / prevention | — |
| PoC | poc.py |
| Source | 2026/CVE-2026-54523/ |
Details¶
English | 한국어
Description¶
Kyverno is a policy engine designed for cloud native platform engineering teams. From 1.18.0 until 1.18.2, the NamespacedMutatingPolicy CEL compiler exposes the generator library to matchConditions, allowing a namespace-scoped policy to invoke generator.apply(namespace, resources) with an arbitrary target namespace. The validation in pkg/cel/policies/mpol/validate.go checks that the policy compiles but does not enforce namespace scope, and GenerateResources in pkg/cel/libs/context.go does not reject the cross-namespace target. A user who can create NamespacedMutatingPolicy objects in one namespace can cause the admission controller, operating with cluster-wide privileges, to create ConfigMaps, NetworkPolicies, Secrets, RoleBindings, and other resources in another namespace, enabling unauthorized modification and potential privilege escalation. This issue is fixed in version 1.18.2.
Vulnerability Details¶
| Property | Value |
|---|---|
| CVE ID | CVE-2026-54523 |
| Type | RCE |
| CVSS Score | 9.6 |
Proof of Concept¶
Download¶
# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-54523/poc.py
Usage¶
# Run PoC against target
python3 poc.py --target <TARGET_URL>
# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>
⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.
Test Lab¶
This repository includes a Docker-based test environment with both vulnerable and patched applications.
Quick Start¶
# Clone and navigate to CVE directory
cd CVE-2026-54523
# Start both applications
docker-compose up -d
# Run tests
./run-tests.sh # Linux/Mac
./run-tests.ps1 # Windows PowerShell
Application Endpoints¶
| Application | URL | Status |
|---|---|---|
| Vulnerable App | http://localhost:8080 | Shows vulnerability |
| Patched App | http://localhost:8081 | Demonstrates fix |
Directory Structure¶
├── README.md # English documentation
├── README_KO.md # Korean documentation
├── poc.py # PoC detection script
├── docker-compose.yml # Container orchestration
├── run-tests.sh # Linux/Mac test runner
├── run-tests.ps1 # Windows test runner
├── vulnerable-app/ # Vulnerable version
│ ├── app.py
│ ├── Dockerfile
│ └── requirements.txt
└── patched-app/ # Fixed version
├── app.py
├── Dockerfile
└── requirements.txt
References¶
- https://github.com/kyverno/kyverno/commit/0919553c0ea1904f8d891280c92018da97946a06
- https://github.com/kyverno/kyverno/commit/5164bcdeda5b57678bc2d7a03ecc2cbb02982dae
- https://github.com/kyverno/kyverno/pull/16238
- https://github.com/kyverno/kyverno/releases/tag/v1.18.2
- https://github.com/kyverno/kyverno/security/advisories/GHSA-79gf-7frw-68m9
- https://github.com/kyverno/sdk/commit/6573937441443e1ba5af9fbb28d5c0f20297f9df
- https://github.com/kyverno/kyverno/security/advisories/GHSA-79gf-7frw-68m9
Generated by PoC Generator on 2026-08-30T19:45:54.916270125
Frequently asked questions¶
What is CVE-2026-54523?¶
CVE-2026-54523 is a Critical (9.6) vulnerability: Kyverno is a policy engine designed for cloud native platform engineering teams.. This entry ships a detection-only PoC and a Docker test lab.
How do I detect CVE-2026-54523?¶
Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.
How do I block or mitigate CVE-2026-54523?¶
Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.
For authorized security testing and research only. See the full source and NVD record.