SSRF in F5 Big-Ip
CVE-2026-66842
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.
Vulnerability class: SSRF (Server-Side Request Forgery)
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
Weakness classification (CWE)
References
- f5sirt@f5.com (vendor-advisory)
Frequently asked questions
- What is CVE-2026-66842?
- CVE-2026-66842 is a high-severity vulnerability in F5 Big-Ip, classified under Server-Side Request Forgery (SSRF). CVSS score: 8.8/10. Published 2026-09-02.
- How severe is CVE-2026-66842?
- High severity. CVSS v3 base score is 8.8 out of 10.