CVE-2021-3606

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-07-02 · updated 2026-06-17
Weakness: CWE-427

Description

OpenVPN before version 2.5.3 on Windows allows local users to load arbitrary dynamic loadable libraries via an OpenSSL configuration file if present, which allows the user to run arbitrary code with the same privilege level as the main OpenVPN process (openvpn.exe).

Affected products

OpenVPN: before 2.5.3 — fixed in 2.5.3

How to fix

Upgrade to a fixed version: OpenVPN 2.5.3. Check the vendor advisory for mitigations.

References

https://community.openvpn.net/openvpn/wiki/CVE-2021-3606
https://community.openvpn.net/openvpn/wiki/SecurityAnnouncements
https://community.openvpn.net/openvpn/wiki/CVE-2021-3606
https://community.openvpn.net/openvpn/wiki/SecurityAnnouncements

Get alerted when CVE-2021-3606 or the next vulnerability affects your stack