CVE-2026-4342

HIGH

ingress-nginx comment-based nginx configuration injection

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2026-4342. PoCs published by fearlessresponsesolution, stuartMoorhouse.

AI-analyzed exploit summary This repository contains a functional exploit PoC for CVE-2026-4342, targeting ingress-nginx v1.15.0. The exploit leverages annotation injection to achieve RCE and Kubernetes secret disclosure via Lua code embedded in nginx configuration.

Description

A security issue was discovered in ingress-nginx where a combination of Ingress annotations can be used to inject configuration into nginx. This can lead to arbitrary code execution in the context of the ingress-nginx controller, and disclosure of Secrets accessible to the controller. (Note that in the default installation, the controller can access all Secrets cluster-wide.)

Exploits (2)

github WORKING POC
by fearlessresponsesolution · tsqlpoc
https://github.com/fearlessresponsesolution/cve-pocs/tree/master/pocs/CVE-2026-4342

This repository contains a functional exploit PoC for CVE-2026-4342, targeting ingress-nginx v1.15.0. The exploit leverages annotation injection to achieve RCE and Kubernetes secret disclosure via Lua code embedded in nginx configuration.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: ingress-nginx v1.15.0
No auth needed
Prerequisites: Kubernetes cluster with ingress-nginx v1.15.0 · kubectl and helm access
devstral-2 · analyzed May 20, 2026 Full analysis →
nomisec WORKING POC
by stuartMoorhouse · poc
https://github.com/stuartMoorhouse/CVE-2026-4342

This repository contains a functional exploit PoC for CVE-2026-4342, demonstrating annotation injection in ingress-nginx (< v1.15.1) leading to RCE and secret disclosure via malicious Ingress resources. The exploit leverages the `configuration-snippet` annotation to inject Lua code into nginx config, enabling command execution and Kubernetes API calls.

Classification
Working Poc 95%
Attack Type
Rce | Info Leak
Complexity
Moderate
Reliability
Reliable
Target: ingress-nginx < v1.15.1
Auth required
Prerequisites: Kubernetes cluster access · ability to create Ingress resources · ingress-nginx v1.15.0 deployed
devstral-2 · analyzed Mar 21, 2026 Full analysis →

Scores

CVSS v3 8.8
EPSS 0.0006
EPSS Percentile 18.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-20
Status published
Products (8)
k8s.io/ingress-nginx 0 - 0.0.0-20260319175635-5183b7d86137Go
kubernetes/ingress-nginx 1.15.0
Kubernetes/ingress-nginx < 1.13.9
kubernetes/ingress-nginx < 1.13.9
Kubernetes/ingress-nginx < 1.14.5
Kubernetes/ingress-nginx < 1.15.1
kubernetes/nginx_ingress_controller 1.15.0
kubernetes/nginx_ingress_controller < 1.13.9
Published Mar 19, 2026
Tracked Since Mar 20, 2026