Integer underflow in OpenVPN for Windows - CVE-2026-88964
Published: October 27, 2026
Vulnerability identifier: #VU157723
CSH Severity: Low
CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-88964
CWE-ID: CWE-191
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to potentially cause a denial of service.
The vulnerability exists due to an unsigned integer underflow in OpenVPN option handling when clearing domain_search_list. A local user can trigger the affected clearing operation to potentially disrupt processing through an incorrectly wrapped unsigned value.
Affected software
OpenVPN for Windows
How to mitigate CVE-2026-88964
Install security update from vendor's website.
OpenVPN for Windows - update to 2.7.8