Description
pfSense CE 2.4.5 through 2.9.0 contains an OS command injection vulnerability that allows authenticated WebGUI users with Advanced Admin Access privilege to execute commands as root via Login Protection settings. Attackers can submit sshguard threshold, block time, or detection time values containing newlines or $(...) that are written unvalidated to sshguard.conf and sourced as root on restart.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Netgate | pfSense CE | 2.4.5 – ≤ 2.9.0 | — |
Advisories 1
- WID-SEC-2026-3983 Netgate pfSense: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 15, 2026
References
- https://github.com/abraxas/pfsense-sshguard-crlf exploit technical-description
- https://abraxaslabs.tech/research/pfsense-ce-leftovers technical-description
- https://github.com/pfsense/pfsense/blob/9363ac5b8651a1c7a333180425ce7719070f95f9/src/usr/local/pfSense/include/www/system_advanced_admin.inc#L355-L381 technical-description
- https://github.com/pfsense/pfsense/blob/9363ac5b8651a1c7a333180425ce7719070f95f9/src/etc/inc/syslog.inc#L531-L563 technical-description
- VulnCheck Advisory: Netgate pfSense CE 2.4.5 through 2.9.0 OS Command Injection via system_advanced_admin.php third-party-advisory