# CVE-2020-11810: openvpn: An issue was discovered in OpenVPN 2.4.x before 2.4.9

CVE-2020-11810 is fixed in openvpn on 1 platform, first by openvpn 2.4.4-2ubuntu1.5, released April 26, 2021. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2020-11810
- Priority: Routine
- CVSS: n/a (Low)
- EPSS: 0.0165
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 27, 2020

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | openvpn Ubuntu 18.04.6 LTS (bionic) | 2.4.4-2ubuntu1.5 | [openvpn 2.4.4-2ubuntu1.5](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-openvpn-2.4.4-2ubuntu1.5.md) | Apr 26, 2021 |
| Linux | openvpn Ubuntu 20.04 LTS (focal) | 2.4.7-1ubuntu2.20.04.2 | [openvpn 2.4.7-1ubuntu2.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-openvpn-2.4.7-1ubuntu2.20.04.2.md) | Apr 26, 2021 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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