CVE-2026-66842
BIG-IP and BIG-IQ Configuration utility vulnerability
CVSS Score
8.8
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-918 |
| Vendor | f5 |
| Product | big-ip |
| Published | Sep 2, 2026 |
| Last Updated | Sep 3, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
F5 / BIG-IP
21.1.0 < 21.1.0.1 21.0.0 < 21.0.0.3 17.5.0 < 17.5.1.8 17.1.0 < 17.1.3.4
F5 / BIG-IQ
8.4.0 < 8.4.2.1
Credits
🔍 F5 acknowledges Dan Stefan Alexandru of Pentest-Tools for bringing this issue to our attention and following the highest standards of coordinated disclosure.