CVE-2026-42406 F5 CVE debrief

Who should care

Organizations using F5 BIG-IP and BIG-IQ systems, particularly those with highly privileged users or Certificate Manager roles, should prioritize patching this vulnerability. The ability to execute arbitrary commands could lead to significant compromise of the affected systems.

Technical summary

The vulnerability exists in various F5 BIG-IP and BIG-IQ products, allowing a highly privileged, authenticated attacker to modify configuration objects and run arbitrary commands. Affected products include BIG-IP Access Policy Manager, Advanced Firewall Manager, Advanced Web Application Firewall, and others, across multiple version ranges. The Common Vulnerabilities and Exposures (CVE) score is 8.5, with a CVSS vector of CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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:X.

Defensive priority

High priority due to high CVSS score and potential for significant system compromise.

Recommended defensive actions

• Apply official patches from F5 as soon as possible.
• Limit exposure by restricting access to highly privileged roles.
• Monitor systems for suspicious activity.
• Review and update configuration objects to prevent unauthorized modifications.
• Implement compensating controls to detect and prevent command execution.

Evidence notes

The primary evidence for this vulnerability comes from the official CVE record and the National Vulnerability Database (NVD). The CVE score and details are based on the information provided by these sources. Affected products and versions are listed in the source item URL from the NVD. The vulnerability allows a highly privileged attacker to execute arbitrary commands, which could lead to significant compromise of the affected systems.

Official resources