CVE-2026-53581Public exploitNetwork attack vector

Root file overwrite via unchecked NTP device path

Published Sep 8, 2026 · Updated Sep 9, 2026

Path traversal in OPNsense before 26.1.9 and Business Edition before 26.4_20 allows remote authenticated users to overwrite files as root. The ntpd_configure_gps() and ntpd_configure_pps() functions concatenate the configured GPS or PPS port beneath /dev/ without normalization or validation. Access to the NTP configuration is required; traversal segments can target any existing filesystem path, including root SSH keys or config.xml.

CVSS severity9.0
Critical
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in OPNsense before 26.1.9 and Business Edition before 26.4_20 allows remote authenticated users to overwrite files as root. The ntpd_configure_gps() and ntpd_configure_pps() functions concatenate the configured GPS or PPS port beneath /dev/ without normalization or validation. Access to the NTP configuration is required; traversal segments can target any existing filesystem path, including root SSH keys or config.xml.

The record

CVE
CVE-2026-53581
Published
Sep 8, 2026
Updated
Sep 9, 2026
Vendor
Deciso B.V.
Product
OPNsense
Classifications
CWE-73, CWE-22, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 26.1.9
  2. Affected versionversion=< 26.4_20

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Deciso B.V. · OPNsenseversion=< 26.1.9; version=< 26.4_20

Published CVSS scores

9.0GitHubCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-73External Control of File Name or Path
CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1565.001Stored Data Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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