CVE-2026-56434
6.5 · MEDIUMOverview
CVE-2026-56434 is a medium-severity vulnerability affecting f5 nginx_gateway_fabric. It was published on July 15, 2026 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssi_module module. This vulnerability may exist when the Server-Side Includes (SSI), proxy_pass, and proxy_buffering off directives are configured. With this configuration, an unauthenticated attacker with man-in-the-middle (MITM) ability to control responses from an upstream server may be able to cause a use-after-free in the NGINX worker process. This issue may lead to limited modification of memory or a restart of the NGINX worker process.
Impact:
This vulnerability may allow remote attackers to have limited control to modify memory contents or restart the NGINX worker process. 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.
Remediation
Check the references section for vendor advisories and patches from f5. Update nginx_gateway_fabric to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| f5 | nginx_gateway_fabric | 1.3.0 | Affected |
| f5 | nginx_ingress_controller | 3.5.0 | Affected |
| f5 | nginx_plus | >= 37.0.0.1, < 37.0.3.1 | Affected |
| f5 | waf | 4.11.0 | Affected |
References
Frequently Asked Questions
What is CVE-2026-56434?
CVE-2026-56434 is a medium-severity vulnerability affecting f5 nginx_gateway_fabric. It was published on July 15, 2026 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
How severe is CVE-2026-56434?
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-56434?
Check the references section for vendor advisories and patches from f5. Update nginx_gateway_fabric to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-56434?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-56434 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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