Vulnerability · Published May 13, 2026 · Assigned by f5

CVE-2026-39455BIG-IP Configuration utility vulnerability

High 7.5

In plain English

A high-severity security flaw in BIG-IP from F5. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.3%top 77.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

When the BIG-IP Configuration utility is configured to use Lightweight Directory Access Protocol (LDAP) authentication, undisclosed traffic can cause the httpd process to exhaust the available file descriptors. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Affected products (as reported)

Vendor	Product	Versions
F5	BIG-IP	21.0.0 – before 21.0.0.217.5.0 – before 17.5.1.617.1.0 – before 17.1.3.216.1.0 – before *

Weakness: CWE-772 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://my.f5.com/manage/s/article/K000160874 vendor-advisory, patch