CVE-2026-42409 BIG-IP HTTP/2 vulnerability
Attackers can cause a denial of service by triggering a null dereference in TMM when specific HTTP/2 and iRule configurations are active.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-42409?
CVE-2026-42409 is a high-severity vulnerability in F5 Big-Ip Access Policy Manager, published on 13 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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 versions which have reached End of Technical Support (EoTS) are not evaluated.
Weakness: CWE-476
Which versions are affected by CVE-2026-42409?
It affects 23 products.
Products include F5 Big-Ip Access Policy Manager, F5 Big-Ip Advanced Firewall Manager, F5 Big-Ip Advanced Web Application Firewall, F5 Big-Ip Analytics, F5 Big-Ip Application Acceleration Manager, F5 Big-Ip Application Security Manager and 17 more.
How do I fix CVE-2026-42409?
No fix has been published for CVE-2026-42409 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-42409 being exploited?
There is no known exploitation of CVE-2026-42409 in the wild and no public exploit code.
Other vulnerabilities in F5 Big-Ip Access Policy Manager
- CVE-2023-46747 F5 BIG-IP Configuration Utility Authentication Bypass
- CVE-2022-1388 F5 BIG-IP Missing Authentication
- CVE-2021-22986 F5 BIG-IP and BIG-IQ Centralized Management iControl REST Remote Code Execution
- CVE-2021-22991 F5 BIG-IP Traffic Management Microkernel Buffer Overflow
- CVE-2020-5902 F5 BIG-IP Traffic Management User Interface (TMUI) Remote Code Execution
Sources
Also known as GHSA-qj39-79pv-x52r.