Vulnerability · Published Jul 30, 2026 · Assigned by OpenVPN
CVE-2026-11771
High 7.0
In plain English
A high-severity stack buffer overflow in OpenVPN from OpenVPN. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)7.0High
Exploit odds (30 days)0.4%top 68.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
OpenVPN version 2.1.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows attackers via an off-by-one buffer write in the NTLM proxy authentication to potentially cause a crash via a crafted NTLM response from a malicious proxy server
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | openvpn | 2.7.5-r0 | ALPINE-CVE-2026-11771 |
| Debian:12 | openvpn | 2.6.14-0+deb12u2 | DEBIAN-CVE-2026-11771 |
| Debian:13 | openvpn | 2.6.14-1+deb13u3 | DEBIAN-CVE-2026-11771 |
| Debian:14 | openvpn | 2.7.5-1 | DEBIAN-CVE-2026-11771 |
| Ubuntu:24.04:LTS | openvpn | 2.6.19-0ubuntu0.24.04.3 | UBUNTU-CVE-2026-11771 |
| Ubuntu:25.10 | openvpn | no fix listed | UBUNTU-CVE-2026-11771 |
| Ubuntu:26.04:LTS | openvpn | 2.7.0-1ubuntu1.2 | UBUNTU-CVE-2026-11771 |
Affected products (as reported)
Weakness: CWE-193, CWE-121, CWE-787 · Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H