Vulnerability · Published Sep 8, 2026 · Assigned by GitHub_M
CVE-2026-53581ntp: write path traversal
Critical 9.0
In plain English
A critical-severity path traversal in core from opnsense. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities).
Official description
OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.9 of opnsense/core and version 26.4_20 of BE/opnsense/core, a path traversal vulnerability in the NTP configuration module allows an attacker to overwrite arbitrary files on the system as the root user. By manipulating the GPS or PPS serial port parameter, an attacker with access to the NTP configuration can escape the intended directory and force the system to write user-controlled data to any file on the filesystem. Version 26.1.9 of opnsense/core and version 26.4_20 of BE/opnsense/core patch the issue.
Affected products (as reported)
Weakness: CWE-22, CWE-73 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:H
References
- https://github.com/opnsense/core/security/advisories/GHSA-872g-g543-j37m x_refsource_CONFIRM