Is CVE-2026-11771 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-11771 being exploited in the wild.

How severe is CVE-2026-11771?

Informational severity, with a CVSS score of 7, published 30 July 2026.

Which products and versions are affected?

Openvpn 2.1.0 through 2.6.20, 2.7_alpha1 through 2.7.4.

Is there a fix for CVE-2026-11771?

A patch was published on 2026-07-01: Versions 2.6.21 and 2.7.5 released to address the issue. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-11771 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-11771?

Check whether you run Openvpn at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-11771: OpenVPN off-by-one buffer write in NTLM proxy authentication

CVE-2026-11771 · Severity: info · CVSS 7 · Published 2026-07-30

OpenVPN is a widely used software for creating secure private network connections. A vulnerability in how it handles authentication with certain proxy servers could allow a malicious proxy to crash the OpenVPN application. This could lead to a denial of service, preventing users from connecting to their corporate networks or secure resources.

Technologies: Openvpn. Vendors: Openvpn.

Quick answers

Is CVE-2026-11771 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-11771 being exploited in the wild.
How severe is CVE-2026-11771?: Informational severity, with a CVSS score of 7, published 30 July 2026.
Which products and versions are affected?: Openvpn 2.1.0 through 2.6.20, 2.7_alpha1 through 2.7.4.
Is there a fix for CVE-2026-11771?: A patch was published on 2026-07-01: Versions 2.6.21 and 2.7.5 released to address the issue. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-11771 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-11771?: Check whether you run Openvpn at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An off-by-one error (CWE-193) leading to a stack-based buffer overflow (CWE-121) exists in OpenVPN's NTLM proxy authentication component. The vulnerability is triggered when the OpenVPN client receives a specially crafted NTLM response from a malicious or compromised proxy server. While the primary impact is a denial of service (application crash), the underlying root cause is an out-of-bounds write. Exploitation requires the client to be configured to use NTLM authentication through a proxy. The issue has been addressed in OpenVPN versions 2.6.21 and 2.7.5.

Affected products

OpenVPN OpenVPN 2.1.0 through 2.6.20, 2.7_alpha1 through 2.7.4

Timeline

2026-07-01: patched: Versions 2.6.21 and 2.7.5 released to address the issue.
2026-07-30: disclosed: CVE-2026-11771 published.

References

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