CVE-2026-42406: F5 BIG-IP · Privilege Defined With Unsafe Actions
Affects F5 BIG-IPSource CVE Database V5
Not known to be exploited · CVSS 8.7 High · fixed in 21.0.0.2 : patch F5 BIG-IP soon.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 21.0.0.2, 17.5.1.6, 17.1.3.2
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 13 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade F5 BIG-IP to 21.0.0.2, 17.5.1.6 or 17.1.3.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| F5BIG-IP | Affected
| Fixed in
|
| F5BIG-IQ | Affected
| Fixed in– |
AI-suggested
If you cannot patch yet, organizations should carefully control and monitor access to the Certificate Manager role to limit exposure. No vendor-provided patches or temporary fixes are currently available.
Description
CVE-2026-42406 is a high-severity vulnerability in F5 BIG-IP and BIG-IQ systems. It allows a highly privileged, authenticated attacker with at least the Certificate Manager role to modify configuration objects that enable running arbitrary commands. This vulnerability affects multiple versions including 21.0.0, 17.5.0, 17.1.0, and 16.1.