CVE-2020-11810

Published: 27 April 2020

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.

Priority

Low

CVSS 3 base score: 3.7

Status

Package Release Status
openvpn
Launchpad, Ubuntu, Debian
Upstream
Released (2.4.9-1)
Ubuntu 21.04 (Hirsute Hippo) Not vulnerable
(2.5.1-1ubuntu1)
Ubuntu 20.04 LTS (Focal Fossa)
Released (2.4.7-1ubuntu2.20.04.2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (2.4.4-2ubuntu1.5)
Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(code not present)
Ubuntu 14.04 ESM (Trusty Tahr) Not vulnerable
(code not present)
Patches:
Upstream: https://github.com/OpenVPN/openvpn/commit/37bc691e7d26ea4eb61a8a434ebd7a9ae76225ab
Upstream: https://github.com/OpenVPN/openvpn/commit/f7b318f811bb43c0d3aa7f337ec6242ed2c33881 (2.4)