SB2026051424 - Remote denial of service in BIG-IP FastL4 virtual server
Published: May 14, 2026
Security Bulletin ID
SB2026051424
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Adjecent network
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Infinite loop (CVE-ID: CVE-2026-42781)
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.
Remediation
Install update from vendor's website.