CVE-2026-4342 ingress-nginx comment-based nginx configuration injection
Attackers can inject nginx configuration via Ingress annotations to execute arbitrary code and read cluster secrets in ingress-nginx.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-4342?
CVE-2026-4342 is a high-severity code injection vulnerability in Kubernetes ingress-nginx, published on 19 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.)
Weakness: CWE-20
Which versions are affected by CVE-2026-4342?
3 open source packages ship an affected version, including k8s.io/ingress-nginx. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
k8s.io/ingress-nginx Go | All versions | 0.0.0-20260319175635-5183b7d86137 |
k8s.io/ingress-nginx Go | All versions | 0.0.0-20260319175635-5183b7d86137 |
k8s.io/ingress-nginx Go | All versions | 0.0.0-20260319175635-5183b7d86137 |
Products include Kubernetes Nginx Ingress Controller.
How do I fix CVE-2026-4342?
Upgrade k8s.io/ingress-nginx to 0.0.0-20260319175635-5183b7d86137 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-4342 being exploited?
There is no known exploitation of CVE-2026-4342 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Kubernetes ingress-nginx
Sources
Also known as GHSA-f53h-mxv9-cp98, GO-2026-4796.