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
References (3)
Core 3
Core References
Vendor Advisory vendor-advisory
https://community.openvpn.net/Security%20Announcements/CVE-2026-11771
Release Notes release-notes
https://community.openvpn.net/ReleaseHistory#openvpn-275-released-1-july-2026
Release Notes release-notes
https://community.openvpn.net/ReleaseHistory#openvpn-2621-released-1-july-2026
Scores
CVSS v4
7.0
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-121
CWE-193
CWE-787
Status
published
Products (2)
OpenVPN/OpenVPN
2.1.0 - 2.6.20
OpenVPN/OpenVPN
2.7_alpha1 - 2.7.4
Published
Jul 30, 2026
Tracked Since
Jul 30, 2026