Answer in brief
CVE-2026-66842 records a High severity (CVSS 8.8) vulnerability in BIG-IP and BIG-IQ Configuration utility vulnerability. The current sources do not mark it as known exploited. The current feed maps F5/BIG-IP (generic), F5/BIG-IQ (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps F5/BIG-IP (generic), F5/BIG-IQ (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| F5/BIG-IPgeneric | >=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 | 21.1.0.1, 21.0.0.3, 17.5.1.8, 17.1.3.4 |
| F5/BIG-IQgeneric | >=8.4.0 <8.4.2.1 | 8.4.2.1 |
Published upstream
Sep 2, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 3, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 2, 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.
Quoted source text, attributed separately from HOL analysis.