NetBird client: Command injection via SSH config Match line from peer FQDN
Summary
The NetBird desktop client writes a system-wide OpenSSH drop-in file that embeds peer FQDNs or hostnames unescaped into a double-quoted Match host directive. A malicious or compromised peer can use a double quote in its name to inject SSH directives, including exec commands. These commands run locally as any user who next runs ssh on the affected host, which can lead to full compromise of that user's context. Affected are Linux, macOS, Windows and FreeBSD desktop clients, but not Android or iOS.
Affected
- NetBird 0.60.0 up to and including 0.74.6
- Desktop clients on Linux, macOS, Windows and FreeBSD
- Not affected: Android and iOS apps
Fixed in
- Upgrade to NetBird 0.74.7 or later
Workaround
- No vendor-documented workaround. Upgrading to 0.74.7 or later is the fix.
- Unverified: disabling NetBird SSH config management with NB_DISABLE_SSH_CONFIG=true may help, but it can break NetBird SSH. Confirm with the vendor first.
- Limit who can join the NetBird network and who can add peers.
Exploitation
- Unknown whether exploited in the wild; no public proof of concept found in the sources reviewed.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- EPSS reported at about 0.6%.
Our recommendation
- Upgrade all NetBird desktop clients to 0.74.7 or later, including packages from distributions and container images.
- Check which NetBird version your distribution or container image actually ships.
- Until patched, restrict who can join the network and add peers, and avoid using affected hosts for sensitive administrative SSH work.
- Review /etc/ssh/ssh_config.d/99-netbird.conf (or the Windows equivalent) for unexpected directives.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- GitHub Security Advisory GHSA-xmg2-v32j-x2hf github.com
- NetBird v0.74.7 release github.com
- Fix pull request #6805 github.com
- OSV entry CVE-2026-105429 osv.dev
- Compare v0.74.6...v0.74.7 github.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 08:32.
Original description (NVD)
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.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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