CVE-2023-53689: Nagios Fusion · XSS or 'Cross-site Scripting'
Affects Nagios FusionSource CVE Database V5
Not known to be exploited · CVSS 6.0 Medium : upgrade to 4.2.0 when convenient.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 58% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.2.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 30 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Upgrade Nagios Fusion to 4.2.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Nagios Fusion | Affected
| Fixed in
|
AI-suggested
European organizations should take the following specific mitigation steps: 1) Immediately upgrade Nagios Fusion to version 4.2.0 or later once available, as this version addresses the vulnerability. 2) Until a patch is applied, restrict access to the license key configuration interface to a minimal set of trusted administrators and consider network segmentation or VPN access controls to limit exposure. 3) Implement web application firewalls (WAFs) with rules to detect and block reflected XSS payloads targeting Nagios Fusion URLs. 4) Educate administrators on the risks of clicking untrusted links, especially those related to Nagios Fusion management. 5) Monitor logs for unusual access patterns or suspicious URL parameters that may indicate exploitation attempts. 6) Enforce multi-factor authentication (MFA) for administrative access to reduce the impact of stolen credentials. 7) Regularly review and audit Nagios Fusion user accounts and permissions to ensure least privilege principles are enforced. 8) Consider deploying Content Security Policy (CSP) headers to mitigate the impact of XSS attacks by restricting script execution sources.
Description
CVE-2023-53689 is a reflected cross-site scripting (XSS) vulnerability in Nagios Fusion versions prior to 4.2.0, specifically in the license key configuration flow. An attacker can craft a malicious URL that, when visited by an authenticated user with administrative privileges, executes attacker-controlled scripts in the user's browser. This can lead to session or credential theft and unauthorized administrative actions, although the server itself is not directly compromised. The vulnerability requires user interaction and high privileges but no authentication bypass. It has a CVSS score of 6.0 (medium severity). European organizations using Nagios Fusion for IT infrastructure monitoring should prioritize patching or mitigating this issue to prevent browser-based attacks targeting administrators.