Description
OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.8, an authenticated Remote Code Execution (RCE) vulnerability in the OPNsense core allows a user with user-management privileges to execute arbitrary system commands as root. An attacker can bypass input validation by formatting their malicious payload as a compliant email address, allowing shell commands to reach the underlying operating system. The flaw exists in the local user synchronization flow, within core/src/opnsense/scripts/auth/sync_user.php. This vulnerability is fixed in 26.1.8.
Affected products
opnsense: opnsense
References2
- github.com/opnsense/core/security/advisories/GHSA-f59w-m967-9rf6 ExploitMitigationVendor Advisory
- github.com/opnsense/core/security/advisories/GHSA-f59w-m967-9rf6 ExploitMitigationVendor Advisory
Metrics
- CVSS 3.1
-
9.1
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - EPSS — exploit probability
- 6% percentile: 93 · as of 14 November 2026
- CWE
- CWE-78
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