Vulnerability in F5 Big-Ip
CVE-2026-39455
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.005 (43.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- F5 Big-Ip — versions 21.1.0, 21.0.0, 17.5.0
- F5 Big-Ip Access Policy Manager — versions 21.0.0
- F5 Big-Ip Advanced Firewall Manager — versions 21.0.0
- F5 Big-Ip Advanced Web Application Firewall — versions 21.0.0
- F5 Big-Ip Analytics — versions 21.0.0
- F5 Big-Ip Application Acceleration Manager — versions 21.0.0
- F5 Big-Ip Application Security Manager — versions 21.0.0
- F5 Big-Ip Application Visibility And Reporting — versions 21.0.0
- F5 Big-Ip Automation Toolchain — versions 21.0.0
- F5 Big-Ip Carrier-Grade Nat — versions 21.0.0
Weakness classification (CWE)
References
- my.f5.com/manage/s/article/K000160874 (vendor-advisory, Mitigation, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-39455?
- CVE-2026-39455 is a high-severity vulnerability in F5 Big-Ip, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 7.5/10. Published 2026-05-13.
- How severe is CVE-2026-39455?
- High severity. CVSS v3 base score is 7.5 out of 10.