Which versions of F5 BIG-IP are affected by EUVD-2026-30004?

F5 BIG-IP Traffic Management Microkernel (TMM) contains a denial-of-service vulnerability affecting UDP virtual servers with Client SSL and Dynamic Record Sizing enabled, allowing unauthenticated…. A patch is available.

How to fix or mitigate EUVD-2026-30004?

Within 24 hours: Identify all F5 BIG-IP instances running affected versions with UDP virtual servers configured using Client SSL profiles with Allow Dynamic Record Sizing enabled. Within 7 days: Apply vendor-released patch per F5 advisory K000160901 to all affected BIG-IP systems, prioritizing production load balancers. Within 30 days: Validate patch deployment across all BIG-IP instances and verify UDP virtual server functionality with Client SSL profiles post-remediation.

F5 BIG-IP EUVD-2026-30004

Q: What is the CVSS score of EUVD-2026-30004?

EUVD-2026-30004 has a CVSS 4.0 base score of 8.7 (High). 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. EPSS exploitation probability: 0.1%.

| CVE-2026-42920 HIGH

Loop with Unreachable Exit Condition (Infinite Loop) (CWE-835)

2026-05-13 f5

GHSA-xgx2-84j2-cx9m

Denial Of Service Big Ip

8.7

CVSS 4.0 · Vendor: f5

Severity by source

Vendor (f5) PRIMARY

8.7 HIGH

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

Primary rating from Vendor (f5) · only source for this CVE.

CVSS VectorVendor: f5

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Re-analysis Queued

May 13, 2026 - 16:22 vuln.today

cvss_changed

CVSS changed

May 13, 2026 - 16:22 NVD

7.5 (HIGH) 8.7 (HIGH)

Analysis Generated

May 13, 2026 - 15:46 vuln.today

CVE Published

May 13, 2026 - 14:12 nvd

HIGH 7.5

DescriptionCVE.org

When a Client SSL profile is configured with Allow Dynamic Record Sizing on a UDP virtual server, 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.

AnalysisAI

Traffic Management Microkernel (TMM) in F5 BIG-IP terminates when processing specific traffic against UDP virtual servers configured with Client SSL profiles having Allow Dynamic Record Sizing enabled. Remote unauthenticated attackers can trigger complete service denial by sending crafted traffic, causing TMM process crashes. F5 has released patches per advisory K000160901.

Technical ContextAI

This vulnerability affects F5 BIG-IP's Traffic Management Microkernel (TMM), the core data plane component responsible for processing network traffic. The issue manifests when SSL/TLS dynamic record sizing optimization - a performance feature that adjusts TLS record sizes based on connection characteristics - is enabled on Client SSL profiles applied to UDP virtual servers. The CWE-835 classification indicates an infinite loop vulnerability, suggesting the undisclosed traffic pattern causes TMM to enter an unrecoverable loop state leading to process termination. UDP virtual servers with SSL profiles represent an uncommon but valid configuration for protocols like DTLS (Datagram TLS), used in VPNs and secure UDP applications. The combination of UDP transport with dynamic SSL record sizing creates a code path where malformed or unexpected packet sequences trigger the loop condition.

RemediationAI

Apply vendor-released patches detailed in F5 Security Advisory K000160901 (https://my.f5.com/manage/s/article/K000160901), which specifies exact fixed versions for supported BIG-IP releases. Organizations unable to immediately patch should implement configuration-based mitigation: disable Allow Dynamic Record Sizing on Client SSL profiles attached to UDP virtual servers via tmsh command 'modify ltm profile client-ssl [profile_name] ssl-sign-hash none' or through the BIG-IP Configuration utility. This workaround eliminates the vulnerable code path while maintaining SSL/TLS functionality with static record sizing, trading minor performance optimization for security. For environments requiring dynamic record sizing, alternative mitigation involves removing Client SSL profiles from UDP virtual servers and terminating SSL at application layer instead, though this architectural change has significant performance and complexity implications. Audit all UDP virtual server configurations using 'tmsh list ltm virtual' filtered for UDP protocol and cross-reference Client SSL profile assignments to identify exposure.