CVE-2026-42919 PUBLISHED

F5 BIG-IP Appliance Mode Vulnerability

Assigner: f5
Reserved: 30.04.2026 Published: 13.05.2026 Updated: 14.05.2026

A vulnerability exists in BIG-IP systems that may allow an authenticated attacker with administrative access to escalate their privileges. A successful exploit may allow the attacker to cross a security boundary.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:H
CVSS Score: 6.7

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

CVSS 3.1

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

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	High
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.) affected from 16.1.0 to * (excl.)

Credits

F5 finder

References

https://my.f5.com/manage/s/article/K000158971

Problem Types

CWE-121 Stack-based Buffer Overflow CWE