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Vulnerability record · CVE-2021-37346 · published 13 August 2021

CVE-2021-37346: Nagios XI WatchGuard Wizard OS command injection RCE

Nagios · Nagios Xi Watchguard Wizard

The Nagios XI WatchGuard Wizard before version 1.4.8 fails to neutralise special elements used in an OS command, allowing OS command injection. Because the flaw is remotely reachable with no privileges or user interaction, it can lead to full remote code execution on the Nagios XI host.

9.8 CVSS 3.1 Critical EPSS 74% · top 0.5% CWE-78 · OS command injection
9.8CVSS 3.1 base score, v2 7.5
74%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

Nagios XI WatchGuard Wizard before version 1.4.8 is vulnerable to remote code execution through Improper neutralisation of special elements used in an OS Command (OS Command injection).

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

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 18 September 2026. Confidence: medium.

critical priorityCVSS 9.8 with network reachability, no authentication and no user interaction, combined with a very high EPSS percentile, makes this a top remediation priority.

What it is

The Nagios XI WatchGuard Wizard before version 1.4.8 fails to neutralise special elements used in an OS command, allowing OS command injection. Because the flaw is remotely reachable with no privileges or user interaction, it can lead to full remote code execution on the Nagios XI host.

Impact

An unauthenticated attacker can execute arbitrary operating system commands on the Nagios XI server, gaining control of the monitoring host and any credentials or data it holds.

Attack surface

Reachable over the network via the WatchGuard Wizard component of Nagios XI; the CVSS vector indicates no authentication (PR:N) and no user interaction (UI:N) are required.

Exploitation

Not listed in CISA KEV and no public exploit or ransomware use is documented in the record, but EPSS is very high at 0.736 (99.4th percentile), indicating elevated likelihood of exploitation activity.

What to do

  • Upgrade the Nagios XI WatchGuard Wizard to version 1.4.8 or later.
  • Apply the vendor change-log release containing the fix and verify the wizard version after upgrade.
  • Restrict network access to the Nagios XI web interface to trusted management networks.
  • Monitor and audit the Nagios XI host for unexpected child processes spawned by the web server.

Detection

  • Alert on web server or Nagios XI processes spawning shell or system utilities (sh, bash, cmd, wget, curl).
  • Review Nagios XI and web server logs for requests to WatchGuard Wizard endpoints containing shell metacharacters.
  • Baseline and monitor outbound connections from the Nagios XI host for command-and-control or download activity.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://www.nagios.com/downloads/nagios-xi/change-log/ Release NotesVendor Advisory
https://www.nagios.com/downloads/nagios-xi/change-log/ Release NotesVendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2021-37346), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.