CVE-2026-42409: BIG-IP HTTP/2 vulnerability

Published May 13, 2026
·
Updated

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.

Affected Software

88 affected components
F5 Networks BIG-IP
F5 Big-ip Next Cloud-native Network Functions>=1.1.0<=1.4.0
F5 Big-ip Next Cloud-native Network Functions>=2.0.0<=2.0.2
F5 BIG-IP Next for Kubernetes>=2.0.0<=2.1.0
F5 BIG-IP Access Policy Manager=21.0.0
F5 BIG-IP Advanced Firewall Manager=21.0.0
F5 Big-ip Advanced Web Application Firewall=21.0.0
F5 BIG-IP Analytics=21.0.0
F5 Big-ip Application Acceleration Manager=21.0.0
F5 BIG-IP Application Security Manager=21.0.0
F5 Big-ip Application Visibility And Reporting=21.0.0
F5 Big-ip Automation Toolchain=21.0.0
F5 Big-ip Carrier-grade Nat=21.0.0
F5 BIG-IP Container Ingress Services=21.0.0
F5 Big-ip Ddos Hybrid Defender=21.0.0
F5 Big-ip Domain Name System=21.0.0
F5 BIG-IP Edge Gateway=21.0.0
F5 Big-ip Fraud Protection Service=21.0.0
F5 Big-ip Global Traffic Manager=21.0.0
F5 Big-ip Link Controller=21.0.0
F5 Big-ip Local Traffic Manager=21.0.0
F5 Big-ip Policy Enforcement Manager=21.0.0
F5 BIG-IP SSL Orchestrator=21.0.0
F5 Big-ip Webaccelerator=21.0.0
F5 Big-ip Websafe=21.0.0
F5 BIG-IP Access Policy Manager>=16.1.0<=16.1.6
F5 BIG-IP Advanced Firewall Manager>=16.1.0<=16.1.6
F5 Big-ip Advanced Web Application Firewall>=16.1.0<=16.1.6
F5 BIG-IP Analytics>=16.1.0<=16.1.6
F5 Big-ip Application Acceleration Manager>=16.1.0<=16.1.6
F5 BIG-IP Application Security Manager>=16.1.0<=16.1.6
F5 Big-ip Application Visibility And Reporting>=16.1.0<=16.1.6
F5 Big-ip Automation Toolchain>=16.1.0<=16.1.6
F5 Big-ip Carrier-grade Nat>=16.1.0<=16.1.6
F5 BIG-IP Container Ingress Services>=16.1.0<=16.1.6
F5 Big-ip Ddos Hybrid Defender>=16.1.0<=16.1.6
F5 Big-ip Domain Name System>=16.1.0<=16.1.6
F5 BIG-IP Edge Gateway>=16.1.0<=16.1.6
F5 Big-ip Fraud Protection Service>=16.1.0<=16.1.6
F5 Big-ip Global Traffic Manager>=16.1.0<=16.1.6
F5 Big-ip Link Controller>=16.1.0<=16.1.6
F5 Big-ip Local Traffic Manager>=16.1.0<=16.1.6
F5 Big-ip Policy Enforcement Manager>=16.1.0<=16.1.6
F5 BIG-IP SSL Orchestrator>=16.1.0<=16.1.6
F5 Big-ip Webaccelerator>=16.1.0<=16.1.6
F5 Big-ip Websafe>=16.1.0<=16.1.6
F5 BIG-IP Access Policy Manager>=17.1.0<=17.1.3
F5 BIG-IP Access Policy Manager>=17.5.0<=17.5.1
F5 BIG-IP Advanced Firewall Manager>=17.1.0<=17.1.3
F5 BIG-IP Advanced Firewall Manager>=17.5.0<=17.5.1
F5 Big-ip Advanced Web Application Firewall>=17.1.0<=17.1.3
F5 Big-ip Advanced Web Application Firewall>=17.5.0<=17.5.1
F5 BIG-IP Analytics>=17.1.0<=17.1.3
F5 BIG-IP Analytics>=17.5.0<=17.5.1
F5 Big-ip Application Acceleration Manager>=17.1.0<=17.1.3
F5 Big-ip Application Acceleration Manager>=17.5.0<=17.5.1
F5 BIG-IP Application Security Manager>=17.1.0<=17.1.3
F5 BIG-IP Application Security Manager>=17.5.0<=17.5.1
F5 Big-ip Application Visibility And Reporting>=17.1.0<=17.1.3
F5 Big-ip Application Visibility And Reporting>=17.5.0<=17.5.1
F5 Big-ip Automation Toolchain>=17.1.0<=17.1.3
F5 Big-ip Automation Toolchain>=17.5.0<=17.5.1
F5 Big-ip Carrier-grade Nat>=17.1.0<=17.1.3
F5 Big-ip Carrier-grade Nat>=17.5.0<=17.5.1
F5 BIG-IP Container Ingress Services>=17.1.0<=17.1.3
F5 BIG-IP Container Ingress Services>=17.5.0<=17.5.1
F5 Big-ip Ddos Hybrid Defender>=17.1.0<=17.1.3
F5 Big-ip Ddos Hybrid Defender>=17.5.0<=17.5.1
F5 Big-ip Domain Name System>=17.1.0<=17.1.3
F5 Big-ip Domain Name System>=17.5.0<=17.5.1
F5 BIG-IP Edge Gateway>=17.1.0<=17.1.3
F5 BIG-IP Edge Gateway>=17.5.0<=17.5.1
F5 Big-ip Fraud Protection Service>=17.1.0<=17.1.3
F5 Big-ip Fraud Protection Service>=17.5.0<=17.5.1
F5 Big-ip Global Traffic Manager>=17.1.0<=17.1.3
F5 Big-ip Global Traffic Manager>=17.5.0<=17.5.1
F5 Big-ip Link Controller>=17.1.0<=17.1.3
F5 Big-ip Link Controller>=17.5.0<=17.5.1
F5 Big-ip Local Traffic Manager>=17.1.0<=17.1.3
F5 Big-ip Local Traffic Manager>=17.5.0<=17.5.1
F5 Big-ip Policy Enforcement Manager>=17.1.0<=17.1.3
F5 Big-ip Policy Enforcement Manager>=17.5.0<=17.5.1
F5 BIG-IP SSL Orchestrator>=17.1.0<=17.1.3
F5 BIG-IP SSL Orchestrator>=17.5.0<=17.5.1
F5 Big-ip Webaccelerator>=17.1.0<=17.1.3
F5 Big-ip Webaccelerator>=17.5.0<=17.5.1
F5 Big-ip Websafe>=17.1.0<=17.1.3
F5 Big-ip Websafe>=17.5.0<=17.5.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Configuration

    Disable the HTTP/2 profile on any virtual server that has an iRule containing the HTTP::redirect or HTTP::respond command to avoid triggering the TMM process termination described.

    BIG-IP virtual server HTTP/2 profile = disabled
  2. Configuration

    Remove or modify iRules so they do not use the HTTP::redirect or HTTP::respond commands on virtual servers that have an HTTP/2 profile configured, preventing the condition that can cause TMM to terminate.

    iRule usage of HTTP::redirect or HTTP::respond = remove/modify to avoid usage

Event History

May 13, 2026
CVE Published
via MITRE·02:12 PM
Data Sourced
via MITRE·02:12 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·04:16 PM
DescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2026-42409?

The severity of CVE-2026-42409 is classified as high with a rating of 8.7.

2

How do I fix CVE-2026-42409?

To fix CVE-2026-42409, upgrade to the latest supported software version recommended by F5 that addresses the vulnerability.

3

What systems are affected by CVE-2026-42409?

CVE-2026-42409 affects multiple F5 BIG-IP systems including Access Policy Manager and Application Security Manager.

4

What kind of vulnerability is CVE-2026-42409?

CVE-2026-42409 is a Null Pointer Dereference vulnerability that can cause the Traffic Management Microkernel process to terminate.

5

What should I do if I am using a version of software that has reached End of Technical Support related to CVE-2026-42409?

If you are using a version that has reached End of Technical Support, you should migrate to a currently supported version to ensure continued protection against CVE-2026-42409.

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