All vulnerabilities
CVE-2026-91184

NGINX Gateway Fabric vulnerability

F5 NGINX Gateway FabricWeb servers
Open in ThreatlineRecord JSON
CVSS
8.8High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.48%Chance of exploitation activity in the next 30 days, higher than 40% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in2.8.0Fixed versionCVE List
Published14 Oct 2026Updated 15 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 1

  • NGINX Gateway Fabricaffected: 2.4.0 before 2.8.0CVE List

References 1