OS Command Injection in OpenVPN Server - CVE-2026-84256
Published: September 5, 2026
Vulnerability identifier: #VU147006
CSH Severity: Low
CVSS v4: 1.8 [CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-84256
CWE-ID: CWE-78
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause command-line misbehavior.
The vulnerability exists due to improper neutralization of special characters in CreateProcess() command-line quoting when processing characters that are special to cmd.exe. A remote attacker can provide specially crafted command-line content to cause command-line misbehavior.
Exploitation requires a validation script and a rogue CA.
Affected software
OpenVPN Server
How to mitigate CVE-2026-84256
Install security update from vendor's website.
OpenVPN Server - update to 2.7.7