Someone's attacking a critical 0-day RCE in F5 BIG-IP APM
Attackers are exploiting critical F5 BIG-IP APM zero-day CVE-2026-94127; CISA added it to KEV.
F5 BIG-IP TMUI Authentication Bypass Enables Unauthenticated RCE
CISA: F5 BIG-IP Configuration Utility Authentication Bypass Vulnerability
CVE-2023-46747 is a critical authentication bypass (CVSS 9.8) in the F5 BIG-IP Configuration Utility (TMUI) affecting most BIG-IP modules, including LTM, APM, DNS, AWAF, AFM, ASM, and SSL Orchestrator. By sending undisclosed, specially crafted requests to the TMUI, an attacker with network access to the BIG-IP management port and/or self IP addresses bypasses authentication and can execute arbitrary system commands on the system. No privileges or user interaction are required, and successful exploitation effectively yields full control of the affected BIG-IP deployment. Any organization running vulnerable BIG-IP software is exposed, particularly enterprises, service providers, and government agencies whose management interface or self IPs are reachable. The flaw is being actively exploited: it was added to CISA KEV on 2023-10-31 with known ransomware use, public PoC code exists, and reporting links it to Chinese nation-state actors targeting defense and government networks.
What to do: Upgrade all affected BIG-IP systems to the fixed releases identified in F5 advisory K13763 (17.1.0.1, 16.1.4, 15.1.9, 14.1.5.5, or 13.1.5.1 depending on the train, or later); the CISA KEV listing makes remediation mandatory for federal agencies. As an interim mitigation, restrict network access to the TMUI management port and self IP addresses and apply F5's documented mitigation guidance. Given active nation-state and ransomware exploitation, also audit appliances for indicators of compromise such as unexpected accounts, scheduled tasks, and configuration changes.
| Product | Affected |
|---|---|
| f5 BIG-IP Access Policy Manager | — |
| f5 BIG-IP Advanced Firewall Manager | — |
| f5 BIG-IP Advanced Web Application Firewall | — |
| f5 BIG-IP Carrier-Grade NAT | — |
| f5 BIG-IP DDoS Hybrid Defender | — |
| f5 BIG-IP SSL Orchestrator | — |
| f5 BIG-IP Domain Name System | — |
| f5 BIG-IP Local Traffic Manager | — |
| f5 BIG-IP Policy Enforcement Manager | — |
| f5 BIG-IP Automation Toolchain | — |
| f5 BIG-IP Container Ingress Services | — |
| f5 BIG-IP Application Security Manager | — |
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Undisclosed requests may bypass configuration utility authentication, allowing an attacker with network access to the BIG-IP system through the management port and/or self IP addresses to execute arbitrary system commands. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated
Attackers are exploiting critical F5 BIG-IP APM zero-day CVE-2026-94127; CISA added it to KEV.
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