CVE-2020-11810: Debian Linux

Low severity, CVSS 3.7. EPSS: 1.7% chance of exploitation in the next 30 days.

An issue was discovered in OpenVPN 2.4.x before 2.4.9. An attacker can inject a data channel v2 (P_DATA_V2) packet using a victim's peer-id. Normally such packets are dropped, but if this packet arrives before the data channel crypto parameters have been initialized, the victim's connection will be dropped. This requires careful timing due to the small time window (usually within a few seconds) between the victim client connection starting and the server PUSH_REPLY response back to the client. This attack will only work if Negotiable Cipher Parameters (NCP) is in use.

Affected products

• Debian Debian Linux: version 8.0 only; version 9.0 only; version 10.0 only
• Fedoraproject Fedora: version 30 only; version 32 only
• Openvpn Openvpn: from 2.4.0, before 2.4.9 (fixed in 2.4.9)

Published 2020-04-27. Last modified 2026-06-17.