CVE-2026-44194: OPNsense: RCE on user managment

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 5.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-13 · updated 2026-10-26
Weakness: CWE-78

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: before 26.1.8 — fixed in 26.1.8

How to fix

Upgrade to a fixed version: OPNsense 26.1.8. Check the vendor advisory for mitigations.

References

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