How severe is CVE-2026-42409?

CVE-2026-42409 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-42409 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42409?

CVE-2026-42409 primarily affects F5 Big-ip Next Cloud-native Network Functions. In total, 44 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-42409?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-42409 have an EU (EUVD) identifier?

Yes. CVE-2026-42409 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29999.

When was CVE-2026-42409 published?

CVE-2026-42409 was published on 2026-05-13 and last updated on 2026-06-23.

CVE-2026-42409

CVE-2026-42409 is a high-severity vulnerability in F5 Big-ip Next Cloud-native Network Functions with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.7
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-29999
Weakness: CWE-476
Affected product: F5 Big-ip Next Cloud-native Network Functions
Published: 2026-05-13
Last modified: 2026-06-23

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.

Frequently asked questions

What is 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 versions which have reached End of Technical Support (EoTS) are not evaluated.
How severe is CVE-2026-42409?: CVE-2026-42409 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-42409 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42409?: CVE-2026-42409 primarily affects F5 Big-ip Next Cloud-native Network Functions. In total, 44 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-42409?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-42409 have an EU (EUVD) identifier?: Yes. CVE-2026-42409 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29999.
When was CVE-2026-42409 published?: CVE-2026-42409 was published on 2026-05-13 and last updated on 2026-06-23.

References

https://my.f5.com/manage/s/article/K000159034

Affected products (44)

cpe:2.3:a:f5:big-ip_next_cloud-native_network_functions:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_next_for_kubernetes:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_access_policy_manager:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_advanced_firewall_manager:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_advanced_web_application_firewall:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_analytics:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_acceleration_manager:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_security_manager:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_visibility_and_reporting:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_automation_toolchain:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_carrier-grade_nat:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_container_ingress_services:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_ddos_hybrid_defender:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_domain_name_system:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_edge_gateway:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_fraud_protection_service:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_global_traffic_manager:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_link_controller:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_local_traffic_manager:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_policy_enforcement_manager:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_ssl_orchestrator:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_webaccelerator:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_websafe:21.0.0:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_access_policy_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_advanced_firewall_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_advanced_web_application_firewall:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_analytics:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_acceleration_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_security_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_visibility_and_reporting:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_automation_toolchain:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_carrier-grade_nat:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_container_ingress_services:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_ddos_hybrid_defender:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_domain_name_system:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_edge_gateway:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_fraud_protection_service:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_global_traffic_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_link_controller:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_local_traffic_manager:*:*:*:*:*:*:*:*

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