MSRXCVE-2026-91184
CVE-2026-91184
NGINX Gateway Fabric vulnerability
CVSS 4.0 · CNA
chance of exploitation in the next 30 days (EPSS; higher than 41% of CVEs)
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.
Scores
Affected products
- F5 NGINX Gateway Fabric: 2.4.0 to < 2.8.0
Weakness: CWE-76
1 references (advisories, patches, write-ups)
- https://my.f5.com/manage/s/article/K000162609 · vendor-advisory
Sources: CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.