Description
Race condition in OpenVPN before 2.0.1, when --duplicate-cn is not enabled, allows remote attackers to cause a denial of service (server crash) via simultaneous TCP connections from multiple clients that use the same client certificate.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | openvpn | 2.0.2-1 | — |
| Debian 13 | openvpn | 2.0.2-1 | — |
| Debian 12 | openvpn | 2.0.2-1 | — |
| Debian 3.1 | openvpn | 2.0-1sarge1 | DSA-851-1 |
Advisories 1
- DSA-851-1 openvpn - denial of service Debian Security (DSA / DLA) · Mar 9, 2026
References
- 17103 third-party-advisory
- http://openvpn.net/changelog.html
- 14610 vdb-entry
- MDKSA-2005:145 vendor-advisory
- DSA-851 vendor-advisory
- 16463 third-party-advisory