What’s Vulnerable › Vulnerabilities
CVE-2026-66842: BIG-IP and BIG-IQ Configuration utility vulnerability
- Severity: high (CVSS 8.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-09-02 · updated 2026-09-03
- Weakness: CWE-918
Description
BIG-IP has a vulnerability where an authenticated user of any role may be able to create administrative user accounts through an undisclosed request to Traffic Management User Interface (TMUI). Impact: This vulnerability may allow an authenticated attacker with network access to the BIG-IP management interface to escalate privileges by creating administrative accounts on the BIG-IP system. 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.
Affected products
- F5 BIG-IP APM: from 21.1.0 before 21.1.0.1; from 21.0.0 before 21.0.0.3; from 17.5.0 before 17.5.1.8; from 17.1.0 before 17.1.3.4 — fixed in 17.1.3.4, 17.5.1.8, 21.0.0.3, 21.1.0.1
- F5 BIG-IQ: from 8.4.0 before 8.4.2.1 — fixed in 8.4.2.1
How to fix
Upgrade to a fixed version: F5 BIG-IP APM 17.1.3.4, 17.5.1.8, 21.0.0.3, 21.1.0.1; F5 BIG-IQ 8.4.2.1. Check the vendor advisory for mitigations.
References
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