What is CVE-2026-42409?

CVE-2026-42409 is a high-severity vulnerability in F5 Big-ip, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2026-05-13.

How severe is CVE-2026-42409?

High severity. CVSS v3 base score is 7.5 out of 10.

NULL pointer dereference in F5 Big-ip

CVE-2026-42409

When an HTTP/2 profile and an iRule containing the HTTP::redirect or HTTP::respond command are configured on a virtual server, undisclosed requests can cause the Traffic Management Microkernel (TMM) process to terminate. Note: Software ve…

EPSS: 0.001 (29.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

F5 Big-ip — versions 21.1.0, 21.0.0, 17.5.0
F5 Big-ip Next Cnf — versions 2.0.0, 1.4.0
F5 Big-ip Next For Kubernetes — versions 2.0.0
F5 Big-ip Next Spk — versions 2.0.0, 1.7.0

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

References

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

Frequently asked questions

What is CVE-2026-42409?: CVE-2026-42409 is a high-severity vulnerability in F5 Big-ip, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2026-05-13.
How severe is CVE-2026-42409?: High severity. CVSS v3 base score is 7.5 out of 10.