CVE-2026-41218 is a vulnerability in F5 Networks Big Ip
Published on May 13, 2026
BIG-IP PEM iRules vulnerability
When BIG-IP PEM iRules are configured on a virtual server (iRules using commands starting with CLASSIFICATION::, CLASSIFY::, PEM::, PSC::, and the urlcatquery command), undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Vulnerability Analysis
CVE-2026-41218 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Dangling pointer Vulnerability?
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
CVE-2026-41218 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-41218
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Affected Versions
F5 BIG-IP:- Version 21.1.0 and below * is unaffected.
- Version 21.0.0 and below 21.0.0.1 is affected.
- Version 17.5.0 and below 17.5.1.4 is affected.
- Version 17.1.0 and below 17.1.3.1 is affected.
- Version 16.1.0 and below * is affected.