CVE-2026-42781 PUBLISHED

BIG-IP FastL4 virtual server vulnerability

Assigner: f5
Reserved: 30.04.2026 Published: 13.05.2026 Updated: 13.05.2026

When embedded Packet Velocity Acceleration (ePVA) acceleration is configured, undisclosed local ethernet traffic can cause an increase in ePVA and Traffic Management Microkernel (TMM) resource utilization. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

CVSS Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 6.5

Attack Vector	Adjacent Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

CVSS Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 7.1

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Adjacent	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	F5
Product	BIG-IP
Versions	Default: unknown unaffected from 21.1.0 to * (excl.) affected from 21.0.0 to 21.0.0.1 (excl.) affected from 17.5.0 to 17.5.1.4 (excl.) affected from 17.1.0 to 17.1.3.1 (excl.) unaffected from 16.1.0 to * (excl.)

Credits

F5 finder

References

https://my.f5.com/manage/s/article/K000160862

Problem Types

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