# CVE-2026-52865: F5 NGINX Ingress Controller NULL pointer dereference in Ingress resources

Source: https://junglewise.ai/threats/cve-2026-52865-f5-nginx-ingress-controller-null-pointer-dereference-in-ingress  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-15. Updated: 2026-07-15  
License: CC BY 4.0 with a link back

CVE-2026-52865 · Severity: medium · CVSS 6.5 · Published 2026-07-15

F5 NGINX Ingress Controller, a tool used to manage external access to services in a Kubernetes cluster, is vulnerable to a denial-of-service attack. An authorized user with permissions to modify network resources can submit a specially crafted configuration that causes the controller to crash repeatedly. This results in a disruption of the management system (control plane), though existing network traffic (data plane) remains unaffected.

Technologies: [F5 Nginx Ingress Controller](https://junglewise.ai/threats/technologies/nginx-ingress-controller). Vendors: [F5](https://junglewise.ai/threats/vendors/f5).

## Quick answers

**Is CVE-2026-52865 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-52865 being exploited in the wild.

**How severe is CVE-2026-52865?** Medium severity, with a CVSS score of 6.5, published 15 July 2026.

**Which products and versions are affected?** F5 Nginx Ingress Controller 5.0.0 to 5.5.1, 2026-lts-r1 to 2026-lts-r2.

**Is there a fix for CVE-2026-52865?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-52865 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-52865?** Check whether you run F5 Nginx Ingress Controller 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.

## Technical details

A NULL pointer dereference vulnerability (CWE-476) exists in the F5 NGINX Ingress Controller when processing Ingress or TransportServer resources. An authenticated remote attacker with write access to these Kubernetes resources can inject malformed data that triggers a process termination. The affected control plane process then enters a persistent crash loop as long as the malformed resource exists in the cluster. This issue affects versions 5.0.0 through 5.5.1 and 2026-lts-r1 through 2026-lts-r2; fixes are available in versions 5.5.2 and 2026-lts-r3.

## Affected products

- F5 NGINX Ingress Controller 5.0.0 to 5.5.1, 2026-lts-r1 to 2026-lts-r2

## Timeline

- 2026-07-15: advisory: Original publication date

## References

- [https://my.f5.com/manage/s/article/K000161834](https://my.f5.com/manage/s/article/K000161834)

## Related threats

- [F5 NGINX Ingress Controller configuration injection in CRDs and annotations](https://junglewise.ai/threats/cve-2026-55723-f5-nginx-ingress-controller-configuration-injection-in-crds-and)
- [F5 NGINX memory over-read in SCGI and uWSGI modules](https://junglewise.ai/threats/cve-2026-42946-f5-nginx-memory-over-read-in-scgi-and-uwsgi-modules)
- [NGINX heap buffer overflow in ngx_http_rewrite_module](https://junglewise.ai/threats/cve-2026-42945-nginx-heap-buffer-overflow-in-ngx-http-rewrite-module)
- [F5 NGINX heap buffer over-read in ngx_http_charset_module](https://junglewise.ai/threats/cve-2026-42934-f5-nginx-heap-buffer-over-read-in-ngx-http-charset-module)
- [F5 NGINX Open Source header injection in HTTP/2 proxying](https://junglewise.ai/threats/cve-2026-42926-f5-nginx-open-source-header-injection-in-http-2-proxying)