Vulnerability DatabaseCVE-2026-11771
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CVE-2026-11771
Published:July 30, 2026
Updated:August 06, 2026
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
https://github.com/OpenVPN/openvpn.git (GITHUB):
Affected version(s) >=v2.3.0 <v2.6.21
Fix Suggestion:
Update to version v2.6.21
https://github.com/OpenVPN/openvpn.git (GITHUB):
Affected version(s) >=v2.7_alpha1 <v2.7.5
Fix Suggestion:
Update to version v2.7.5
Related Resources (3)
https://community.openvpn.net/ReleaseHistory#openvpn-275-released-1-july-2026
https://community.openvpn.net/ReleaseHistory#openvpn-2621-released-1-july-2026
https://community.openvpn.net/Security%20Announcements/CVE-2026-11771
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CVSS v4
Base Score:
7
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
HIGH
CVSS v3
Base Score:
6.1
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Out-of-bounds Write
CWE-787
Off-by-one Error
CWE-193
Stack-based Buffer Overflow
CWE-121
EPSS
Base Score:
0.34