CVE-2026-11311
F5 Nginx Gateway Fabric 2.5.0 – 2.6.4
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-11311 is a high-severity Improper Neutralization of Equivalent Special Elements (CWE-76) vulnerability in F5 Nginx Gateway Fabric. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Dynamic Linker Hijacking (T1574.006); ranked at the 46th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-37720
Vulnerability Data
When NGINX Plus is configured as the data plane for NGINX Gateway Fabric, an injection vulnerability exists in the NGINX configuration generator component of NGINX Gateway Fabric. User-supplied string values from the NginxProxy Custom Resource Definition serverTokens field and the…
more
AuthenticationFilter Custom Resource Definition extraAuthArgs field are rendered directly into NGINX configuration templates without sanitization or escaping. An authenticated attacker with permission to create or modify these Custom Resource Definitions may craft values that inject arbitrary NGINX configuration directives. This is a control plane issue; there is no data plane exposure from the vulnerability trigger itself. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
—
—
—
V1.2.1V1.2.3V1.2.5V1.2.8
Mitigating Controls (NIST 800-53 r5) AI
SA-11 requires developer testing and evaluation that can discover failures to neutralize equivalent special elements.
SI-10 requires validation of information inputs, directly stopping incomplete neutralization of equivalent special elements.
SA-8 mandates security engineering principles such as complete input validation and sanitization that cover equivalent special-element forms.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require consistent neutralization of all equivalent special elements during input validation and sanitization.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Logging supports detection of injection attempts but does not prevent the weakness.
Monitoring activities can identify active injection attacks after they occur.
Secure development life cycle mandates input validation and neutralization of all equivalent special elements.
Application security requirements include rules for handling special characters and equivalent encodings.
Secure system architecture principles require consistent canonicalization and neutralization of equivalent inputs.
Secure coding standards directly address proper neutralization of all equivalent special elements.