CVE-2026-66842 PUBLISHED

BIG-IP and BIG-IQ Configuration utility vulnerability

Assigner: f5
Reserved: 29.07.2026 Published: 02.09.2026 Updated: 02.09.2026

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.

Metrics

CVSS Vector: 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
CVSS Score: 8.7

Product Status

Vendor F5
Product BIG-IP
Versions Default: unknown
  • affected from 21.1.0 to 21.1.0.1 (excl.)
  • affected from 21.0.0 to 21.0.0.3 (excl.)
  • affected from 17.5.0 to 17.5.1.8 (excl.)
  • affected from 17.1.0 to 17.1.3.4 (excl.)
Vendor F5
Product BIG-IQ
Versions Default: unaffected
  • affected from 8.4.0 to 8.4.2.1 (excl.)

Workarounds

None

Credits

  • F5 acknowledges Dan Stefan Alexandru of Pentest-Tools for bringing this issue to our attention and following the highest standards of coordinated disclosure. reporter

References

Problem Types

  • CWE-918 Server-Side Request Forgery (SSRF) CWE