CVE-2026-42920: CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop') in F5 BIG-IP
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.
AI Analysis
Technical Summary
This vulnerability, identified as CWE-835 (Loop with Unreachable Exit Condition), exists in F5 BIG-IP when a Client SSL profile is configured with Allow Dynamic Record Sizing on a UDP virtual server. Undisclosed traffic can trigger an infinite loop in the Traffic Management Microkernel (TMM), causing it to terminate and resulting in a denial of service. The affected versions include 16.1.0, 17.1.0, 17.5.0, and 21.0.0. The CVSS v3.1 base score is 7.5, reflecting network attack vector, low attack complexity, no privileges or user interaction required, and an impact limited to availability. No official remediation or patch has been documented as of the published date.
Potential Impact
The primary impact is denial of service due to termination of the Traffic Management Microkernel (TMM) when processing certain UDP traffic with specific SSL profile settings. There is no impact on confidentiality or integrity. This can disrupt network traffic management and potentially cause service outages on affected BIG-IP devices.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, consider disabling Allow Dynamic Record Sizing on UDP virtual servers if feasible to reduce exposure. Monitor vendor communications for updates on patches or official mitigations.
CVE-2026-42920: CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop') in F5 BIG-IP
Description
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability, identified as CWE-835 (Loop with Unreachable Exit Condition), exists in F5 BIG-IP when a Client SSL profile is configured with Allow Dynamic Record Sizing on a UDP virtual server. Undisclosed traffic can trigger an infinite loop in the Traffic Management Microkernel (TMM), causing it to terminate and resulting in a denial of service. The affected versions include 16.1.0, 17.1.0, 17.5.0, and 21.0.0. The CVSS v3.1 base score is 7.5, reflecting network attack vector, low attack complexity, no privileges or user interaction required, and an impact limited to availability. No official remediation or patch has been documented as of the published date.
Potential Impact
The primary impact is denial of service due to termination of the Traffic Management Microkernel (TMM) when processing certain UDP traffic with specific SSL profile settings. There is no impact on confidentiality or integrity. This can disrupt network traffic management and potentially cause service outages on affected BIG-IP devices.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, consider disabling Allow Dynamic Record Sizing on UDP virtual servers if feasible to reduce exposure. Monitor vendor communications for updates on patches or official mitigations.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- f5
- Date Reserved
- 2026-04-30T23:02:47.685Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a049713cbff5d8610dffdfe
Added to database: 5/13/2026, 3:21:55 PM
Last enriched: 5/13/2026, 3:39:21 PM
Last updated: 5/14/2026, 6:46:35 AM
Views: 8
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