CVE-2026-39459: F5 BIG-IP · Least Privilege Violation
Affects F5 BIG-IPSource CVE Database V5
Not known to be exploited · CVSS 7.2 High · fixed in 21.0.0.2 : patch F5 BIG-IP soon.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 17% 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:U/C:H/I:H/A:HExploitation 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
|
AI-suggested
If you cannot patch yet, restrict Manager role assignments to trusted personnel only and monitor for unusual configuration changes. Avoid using versions listed as affected if possible, or consider upgrading to versions not listed once vendor guidance is available.
Description
CVE-2026-39459 is a high-severity vulnerability in F5 BIG-IP affecting iControl REST and TMOS Shell (tmsh). It allows a highly privileged, authenticated attacker with at least the Manager role to create configuration objects that enable running arbitrary commands. This violates the principle of least privilege and could lead to full system compromise. The affected versions include 16.1.0, 17.1.0, 17.5.0, and 21.