CVE-2026-53581

9.0 CRITICAL 0.5% exploit odds Fix listed Disclosure Network gear

What it is

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.

At a glance

Exploitability: Can be exploited over the network with an admin-level account. High risk of data exposure, service disruption.
Exploit odds: 0.5% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-09 19:11 UTC ReservedThe CVE id was reserved by its CNA
2026-09-08 23:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-09-25 14:23 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.5% in the next 30 days (EPSS).
Severity: 9.0 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-09-08 23:17 UTC
Last modified: 2026-09-25 14:23 UTC
Exploit probability: 0.5% · EPSS, next 30 days
Weakness: CWE-22 · Path traversal
Record status: Awaiting Analysis

Attack profile CVSS 3.1 · 9.0

Attack vector: Network
Complexity: Low
Privileges needed: High
User interaction: None
Scope: Changed
Confidentiality: High
Integrity: Low
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-53581.md and follow it. Check whether this project is affected by CVE-2026-53581. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record