Vulnerability in F5 NGINX Ingress Controller

[ Description ]Official description

An authentication and authorization bypass vulnerability exists in F5 NGINX Kubernetes Ingress Controller (NIC) when configured with the `ExternalAuth` policy or Ingress external authentication. Client-supplied X-Forwarded-Prefix, X-Forwarded-URI, X-Original-URI, and X-Forwarded-Method routing and method headers are forwarded unsanitized into the internal authentication subrequest (handled by the NGINX auth_request directive). As a result, an unauthenticated, remote attacker may spoof request attributes evaluated by the external authentication provider. Impact: This vulnerability may allow remote attackers unauthenticated access to protected paths. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• CERT-FR19 Oct 2026CERTFR-2026-AVI-1341

  Multiple vulnerabilities in F5 products Translated from French

  Multiple vulnerabilities have been discovered in F5 products. Some of them allow an attacker to cause remote arbitrary code execution, remote denial of service and a breach of data confidentiality.

  CVE-2026-91184CVE-2026-101019CVE-2026-96615+8 more CVEs
• BSI CERT-Bund14 Oct 2026WID-SEC-2026-3948

  NGINX: Multiple vulnerabilities Translated from German

  Risk highCVE-2026-101025CVE-2026-15176CVE-2026-91184+8 more CVEs

[ References ]References

• my.f5.com/manage/s/article/K000162611