Insufficient verification of data authenticity in OpenVPN Server - CVE-2025-13086
Published: November 27, 2025
Vulnerability identifier: #VU118819
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2025-13086
CWE-ID: CWE-345
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: OpenVPN
Affected software:
OpenVPN Server
OpenVPN Server
Detailed vulnerability description
The vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to improper handling of HMAC verification checks during the three way handshake. A remote attacker can bypass source IP address validation and connect to the server from an IP address that did not initiate the initial connection.
How to mitigate CVE-2025-13086
Install updates from vendor's website.