Advisoriesby IbisF5CVE-2026-66842
F5 BIG-IP: privilege escalation
Fix: upgrade to 21.1.0.1 or later (5 fixed versions below)
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 versions
| Package | Affected | Fixed in |
|---|---|---|
| BIG-IP Product | >= 21.1.0, < 21.1.0.1 | 21.1.0.1 |
| >= 21.0.0, < 21.0.0.3 | 21.0.0.3 | |
| >= 17.5.0, < 17.5.1.8 | 17.5.1.8 | |
| >= 17.1.0, < 17.1.3.4 | 17.1.3.4 | |
| BIG-IQ Product | >= 8.4.0, < 8.4.2.1 | 8.4.2.1 |
Details and references
- CVSS 4.0
- CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/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
- Severity from
- the vendor (its own CVE record or advisory)
- Weakness
- CWE-918