What is CVE-2026-40631?

CVE-2026-40631 is a high-severity vulnerability in F5 Big-ip, classified under Files or Directories Accessible to External Parties. CVSS score: 8.7/10. Published 2026-05-13.

How severe is CVE-2026-40631?

High severity. CVSS v3 base score is 8.7 out of 10.

Vulnerability in F5 Big-ip

CVE-2026-40631

An authenticated attacker with the Resource Administrator or Administrator role can modify configuration objects through iControl SOAP resulting in privilege escalation. Note: Software versions which have reached End of Technical Support…

EPSS: 0.001 (21.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N.

Affected products

F5 Big-ip — versions 21.1.0, 21.0.0, 17.5.0

Weakness classification (CWE)

CWE-552 — Files or Directories Accessible to External Parties

References

f5sirt@f5.com (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-40631?: CVE-2026-40631 is a high-severity vulnerability in F5 Big-ip, classified under Files or Directories Accessible to External Parties. CVSS score: 8.7/10. Published 2026-05-13.
How severe is CVE-2026-40631?: High severity. CVSS v3 base score is 8.7 out of 10.