CVE-2026-53581

ntp: write path traversal

State: Published
Severity: 9.0 Critical
Published: Sep 8, 2026
Updated: Sep 9, 2026
Reserved: Jun 9, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	9.0 Critical	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:H	GitHub_M

Weaknesses

CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-73 External Control of File Name or Path

Affected Products

Product	Versions
coreopnsense	< 26.1.9Affected < 26.4_20Affected

References

https://github.com/opnsense/core/security/advisories/GHSA-872g-g543-j37m

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