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CVE-2021-42237 — Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure…

Key facts

CVE-2021-42237 is a Critical (9.8) vulnerability: Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure…. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2022-03-25), confirming active exploitation in the wild, and is linked to known ransomware campaigns.

Actively exploited — on the CISA KEV catalog

CVE-2021-42237 is listed on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2022-03-25), confirming exploitation in the wild. It is linked to known ransomware campaigns. Federal remediation deadline: 2022-04-15. Prioritise patching and deploy the detection and prevention rules below.
CVE CVE-2021-42237
Severity Critical (9.8)
CISA KEV Actively exploited (added 2022-03-25) · ransomware
Detection / prevention —
PoC poc.py
Source 2021/CVE-2021-42237/

Details

English | 한국어

Description

Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.

Vulnerability Details

Property Value
CVE ID CVE-2021-42237
CVSS Score 9.8

Proof of Concept

Download

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2021/CVE-2021-42237/poc.py

Usage

# Run PoC against target
python3 poc.py --target <TARGET_URL>

# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>

⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.

Test Lab

This repository includes a Docker-based test environment with both vulnerable and patched applications.

Quick Start

# Clone and navigate to CVE directory
cd CVE-2021-42237

# Start both applications
docker-compose up -d

# Run tests
./run-tests.sh    # Linux/Mac
./run-tests.ps1   # Windows PowerShell

Application Endpoints

Application URL Status
Vulnerable App http://localhost:8080 Shows vulnerability
Patched App http://localhost:8081 Demonstrates fix

Directory Structure

├── README.md           # English documentation
├── README_KO.md        # Korean documentation
├── poc.py              # PoC detection script
├── docker-compose.yml  # Container orchestration
├── run-tests.sh        # Linux/Mac test runner
├── run-tests.ps1       # Windows test runner
├── vulnerable-app/     # Vulnerable version
│   ├── app.py
│   ├── Dockerfile
│   └── requirements.txt
└── patched-app/        # Fixed version
    ├── app.py
    ├── Dockerfile
    └── requirements.txt

References

  • http://packetstormsecurity.com/files/164988/Sitecore-Experience-Platform-XP-Remote-Code-Execution.html
  • http://sitecore.com
  • https://blog.assetnote.io/2021/11/02/sitecore-rce/
  • https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1000776
  • http://packetstormsecurity.com/files/164988/Sitecore-Experience-Platform-XP-Remote-Code-Execution.html
  • http://sitecore.com
  • https://blog.assetnote.io/2021/11/02/sitecore-rce/
  • https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1000776
  • https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42237

Generated by PoC Generator on 2026-06-26T03:02:39.463021942

Frequently asked questions

What is CVE-2021-42237?

CVE-2021-42237 is a Critical (9.8) vulnerability: Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure…. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2022-03-25), confirming active exploitation in the wild, and is linked to known ransomware campaigns.

How do I detect CVE-2021-42237?

Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.

How do I block or mitigate CVE-2021-42237?

Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.

Is CVE-2021-42237 actively exploited?

Yes. CVE-2021-42237 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, added 2022-03-25, which means it has been exploited in the wild. CISA also links it to known ransomware campaigns. CISA set a federal remediation deadline of 2022-04-15. Prioritise patching and deploy the detection and prevention rules above.

For authorized security testing and research only. See the full source and NVD record.