Incorrect Calculation of Buffer Size in F5 Networks products - CVE-2026-40618
Published: May 14, 2026
Vulnerability identifier: #VU131394
CSH Severity: Medium
CVSS v4.0: 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:U/U:Green
CVE-ID: CVE-2026-40618
CWE-ID: CWE-131
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: F5 Networks
Affected software:
BIG-IP Next CNF
BIG-IP Next SPK
BIG-IP Next for Kubernetes
BIG-IP
BIG-IP Next CNF
BIG-IP Next SPK
BIG-IP Next for Kubernetes
BIG-IP
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to incorrect calculation of buffer size in the SSL profile when processing undisclosed traffic. A remote attacker can send crafted traffic to cause a denial of service.
This issue affects the data plane only and has no control plane exposure. Exploitation is possible when an SSL profile is configured on a virtual server on BIG-IP Virtual Edition without Intel QuickAssist Technology or on BIG-IP hardware platforms with the crypto.hwacceleration database variable disabled.
How to mitigate CVE-2026-40618
Install security update from vendor's website.