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.
References (1)
Core 1
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/opnsense/core/security/advisories/GHSA-f59w-m967-9rf6
Scores
CVSS v3
9.1
EPSS
0.0635
EPSS Percentile
92.7%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
total
Details
CWE
CWE-78
Status
published
Products (2)
opnsense/core
< 26.1.8
opnsense/opnsense
< 26.1.8
Published
May 13, 2026
Tracked Since
May 14, 2026