CVE-2020-11810: Race Condition
An issue was discovered in OpenVPN 2.4.x before 2.4.9. An attacker can inject a data channel v2 (PDATAV2) 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 PUSHREPLY response back to the client. This attack will only work if Negotiable Cipher Parameters (NCP) is in use.
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is CVE-2020-11810?
CVE-2020-11810 is a vulnerability discovered in OpenVPN 2.4.x before 2.4.9 that allows an attacker to inject a data channel packet using a victim's peer-id.
How severe is CVE-2020-11810?
CVE-2020-11810 has a severity level of medium with a CVSS score of 3.7.
Which software versions are affected by CVE-2020-11810?
The vulnerability affects OpenVPN versions 2.4.x before 2.4.9.
How can I mitigate the vulnerability in OpenVPN?
To mitigate the vulnerability, update OpenVPN to version 2.4.9 or later.
Where can I find more information about CVE-2020-11810?
You can find more information about CVE-2020-11810 in the following references: [Reference 1](https://bugzilla.suse.com/show_bug.cgi?id=1169925), [Reference 2](https://community.openvpn.net/openvpn/ticket/1272), [Reference 3](https://github.com/OpenVPN/openvpn/commit/37bc691e7d26ea4eb61a8a434ebd7a9ae76225ab).