CVE-2026-105429

NetBird client SSH config Match line injection via peer FQDN or hostname allows local command execution

Published Oct 14, 2026 CVSS 4.0 · 8.9 High EPSS < 1% KEV · Not listed
Description
Improper neutralization of special elements in the NetBird client SSH configuration manager (client/ssh/config/manager.go) in NetBird versions 0.60.0 through 0.74.6 allows a malicious or compromised peer to execute arbitrary commands on other NetBird client hosts. The client writes a system-wide OpenSSH drop-in file (/etc/ssh/ssh_config.d/99-netbird.conf, or the equivalent under %PROGRAMDATA%\ssh\ssh_config.d on Windows) that embeds each peer FQDN or hostname inside a double-quoted Match host directive without escaping. A peer name containing a double quote breaks out of the quoted context and injects arbitrary SSH configuration directives, including exec commands, which run locally as any user on the host the next time that user runs ssh. Desktop clients on Linux, macOS, Windows and FreeBSD are affected; the Android and iOS apps are not. The issue is fixed in version 0.74.7, which accepts a peer FQDN or hostname only if it is a valid DNS name.

Remediation

Vendor Solution

Upgrade the NetBird client to version 0.74.7 or later. In this version, buildHostPatterns accepts a peer FQDN or hostname only if it is a plain DNS name, and rejects quotes, whitespace, newlines, commas and SSH pattern metacharacters (pull request #6805).

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Improper neutralization of special elements in the NetBird client SSH configuration manager (client/ssh/config/manager.go) in NetBird versions 0.60.0 through 0.74.6 allows a malicious or compromised peer to execute arbitrary commands on other NetBird client hosts. The client writes a system-wide OpenSSH drop-in file (/etc/ssh/ssh_config.d/99-netbird.conf, or the equivalent under %PROGRAMDATA%\ssh\ssh_config.d on Windows) that embeds each peer FQDN or hostname inside a double-quoted Match host directive without escaping. A peer name containing a double quote breaks out of the quoted context and injects arbitrary SSH configuration directives, including exec commands, which run locally as any user on the host the next time that user runs ssh. Desktop clients on Linux, macOS, Windows and FreeBSD are affected; the Android and iOS apps are not. The issue is fixed in version 0.74.7, which accepts a peer FQDN or hostname only if it is a valid DNS name.
Title NetBird client SSH config Match line injection via peer FQDN or hostname allows local command execution
First Time appeared Netbird
Netbird netbird
Weaknesses CWE-116
CWE-78
CPEs cpe:2.3:a:netbird:netbird:*:*:*:*:*:*:*:*
Vendors & Products Netbird
Netbird netbird
References
Metrics cvssV3_1

{'score': 8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H'}

cvssV4_0

{'score': 8.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
securin
Published
Updated
Oct 16, 2026, 3:31 PM
Reserved
Oct 5, 2026, 12:51 PM
Status
Deferred
Published
Oct 14, 2026, 5:16 AM
Modified
Oct 16, 2026, 7:56 PM