In some circumstances, the Traffic Management Microkernel (TMM) does not properly handle certain malformed Websockets requests/responses, which allows remote attackers to cause a denial-of-service (DoS) or possible remote code execution on the F5 BIG-IP system running versions 13.0.0 - 13.1.0.3 or 12.1.0 - 12.1.3.1.
Severity
CVSS 3.0
8.1 high
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
4.3% chance of exploitation in the next 30 days; higher than 91% of CVEs (scores of 2026-10-31)