Vulnerability in F5 NGINX Gateway Fabric

[ Description ]Official description

Description NGINX Gateway Fabric has a vulnerability when it renders the spec.basic.realm (and spec.jwt.realm) field of a namespaced AuthenticationFilter verbatim, unescaped and unvalidated, into the shared data-plane nginx.conf as auth_basic "<realm>";. A namespaced authenticated attacker that configures AuthenticationFilter CRD to an HTTPRoute/GRPCRoute on a shared Gateway can craft a realm value that closes the quoted directive and the enclosing location {} block and injects arbitrary NGINX directives into that Gateway's data-plane config.  Impact A remote authenticated attacker can send crafted requests to configure NGINX Gateway Fabric AuthenticationFilter CRD and may be able to read every co-located tenant's mounted secrets, SSRF via proxy_pass, reading the pod ServiceAccount token, or hijacking other tenants' routes. There is no data plane exposure; this is a control 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/K000162609