CVE-2026-73570 — A remote code execution vulnerability exists in Zimbra Collaboration (ZCS) before 10.1.20…¶

Key facts

CVE-2026-73570 is a High (8.9) vulnerability: A remote code execution vulnerability exists in Zimbra Collaboration (ZCS) before 10.1.20…. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2026-08-21), confirming active exploitation in the wild.

Actively exploited — on the CISA KEV catalog

CVE-2026-73570 is listed on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2026-08-21), confirming exploitation in the wild. Federal remediation deadline: 2026-08-24. Prioritise patching and deploy the detection and prevention rules below.


CVE	CVE-2026-73570
Severity	High (8.9)
CISA KEV	Actively exploited (added 2026-08-21)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-73570/

Details¶

English | 한국어

Description¶

A remote code execution vulnerability exists in Zimbra Collaboration (ZCS) before 10.1.20 when the optional zimbra-snmp package is installed and SNMP notifications are enabled. Due to improper sanitization of untrusted input during SNMP notification processing, an unauthenticated attacker can send specially crafted SMTP requests that may result in execution of arbitrary operating system commands as the Zimbra user.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-73570
Type	RCE
CVSS Score	8.9

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-73570/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-2026-73570

# 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¶

https://wiki.zimbra.com/wiki/Security_Center
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories

Generated by PoC Generator on 2026-08-16T04:23:05.449629634

Frequently asked questions¶

What is CVE-2026-73570?¶

CVE-2026-73570 is a High (8.9) vulnerability: A remote code execution vulnerability exists in Zimbra Collaboration (ZCS) before 10.1.20…. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2026-08-21), confirming active exploitation in the wild.

How do I detect CVE-2026-73570?¶

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-2026-73570?¶

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-2026-73570 actively exploited?¶

Yes. CVE-2026-73570 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, added 2026-08-21, which means it has been exploited in the wild. CISA set a federal remediation deadline of 2026-08-24. Prioritise patching and deploy the detection and prevention rules above.

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