Review reviewHigh

CVE-2026-41218

F5 BIG-IP, big-ip access policy manager, big-ip advanced firewall manager

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.

CVSS: 8.7
EPSS: 0.26%
CISA KEV: Not listed
Published: 2026.05.14

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.26%

Technical severityCVSS 8.7

Vulnerability overview

Affected product and versions

Product: F5 BIG-IP, big-ip access policy manager, big-ip advanced firewall manager
Affected versions: 21.0.0, 17.5.0, 17.1.0, 16.1.0, >= 17.1.0 <= 17.1.3, >= 17.5.0 <= 17.5.1, >= 16.1.0 <= 16.1.6
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that F5 BIG-IP, big-ip access policy manager, big-ip advanced firewall manager and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: 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:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE: CWE-416