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.
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 | 2.4.9-1 | — |
| Debian 13 | openvpn | 2.4.9-1 | — |
| Debian 12 | openvpn | 2.4.9-1 | — |
| Debian 9 | openvpn | 2.4.0-6+deb9u4 | DLA-2992-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | openvpn | 2.4.7-1ubuntu2.20.04.2 | USN-4933-1 |
| Ubuntu 18.04 LTS | openvpn | 2.4.4-2ubuntu1.5 | USN-4933-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | openvpn | 2.4.3-5.7.1 | SUSE-SU-2021:1577-1 |
| SLES 15 SP2 | openvpn | 2.4.3-5.7.1 | SUSE-SU-2021:1577-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | openvpn | 2.5.3-1.2 | openSUSE-SU-2024:11128-1 |
| openSUSE Leap 15.2 | openvpn | 2.4.3-lp152.6.3.1 | openSUSE-SU-2021:0734-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | openvpn | 2.4.9-r0 | — |
| Alpine v3.23 | openvpn | 2.4.9-r0 | — |
| Alpine v3.22 | openvpn | 2.4.9-r0 | — |
| Alpine v3.21 | openvpn | 2.4.9-r0 | — |
| Alpine v3.20 | openvpn | 2.4.9-r0 | — |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | openvpn | 2.4.9-r0 | — |
| Alpine v3.18 | openvpn | 2.4.9-r0 | — |
| Alpine v3.17 | openvpn | 2.4.9-r0 | — |
| Alpine v3.16 | openvpn | 2.4.9-r0 | — |
| Alpine v3.15 | openvpn | 2.4.9-r0 | — |
| Alpine v3.14 | openvpn | 2.4.9-r0 | — |
| Alpine v3.13 | openvpn | 2.4.9-r0 | — |
| Alpine v3.12 | openvpn | 2.4.9-r0 | — |
| Alpine v3.11 | openvpn | 2.4.9-r0 | — |
| Alpine v3.10 | openvpn | 2.4.9-r0 | — |
Advisories 5
- DLA-2992-1 openvpn - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-4933-1 openvpn vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- openSUSE-SU-2024:11128-1 openvpn-2.5.3-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0734-1 Security update for openvpn SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1577-1 Security update for openvpn SUSE / openSUSE Security Updates · Feb 4, 2026
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/
- FEDORA-2020-c1cb4ebcd9 vendor-advisory
- FEDORA-2020-969414e05b vendor-advisory
- [debian-lts-announce] 20220503 [SECURITY] [DLA 2992-1] openvpn security update mailing-list