Infinite loop in BIG-IP - CVE-2026-42781
Published: May 14, 2026
Vulnerability identifier: #VU131390
CSH Severity: Medium
CVSS v4: 7.1 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-42781
CWE-ID: CWE-835
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to loop with unreachable exit condition in ePVA/fastL4 virtual server ARP when processing undisclosed local ethernet traffic. A remote attacker can send local network traffic to cause a denial of service.
There is no control plane exposure; this is a data plane issue only. Only BIG-IP tenants deployed on the r5000, r10000, r12000, BX110, and BX520 platforms with ePVA are affected.
Affected software
BIG-IP
How to mitigate CVE-2026-42781
Install security update from vendor's website.
BIG-IP - addressed in versions 17.1.3.1, 17.5.1.4, 21.0.0.1