NULL pointer dereference in F5 Networks products - CVE-2026-42409
Published: May 14, 2026
Vulnerability identifier: #VU131391
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-42409
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: F5 Networks
Affected software:
BIG-IP Next CNF
BIG-IP Next SPK
BIG-IP Next for Kubernetes
BIG-IP
BIG-IP Next CNF
BIG-IP Next SPK
BIG-IP Next for Kubernetes
BIG-IP
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a null pointer dereference in the Traffic Management Microkernel (TMM) process when handling undisclosed requests to a virtual server configured with an HTTP/2 profile and an iRule containing the HTTP::redirect or HTTP::respond command. A remote attacker can send a crafted request to cause a denial of service.
This is a data plane issue only, with no control plane exposure.
How to mitigate CVE-2026-42409
Install security update from vendor's website.