URGENT PATCH ALERT • QNAP

      QNAP Fixes High-Severity Flaws: NetBak Replicator RCE and SQL Injection in Qsync Central    

By CyberDudeBivash • October 05, 2025 • Urgent Security Directive

 cyberdudebivash.com |       cyberbivash.blogspot.com 

Share on XShare on LinkedIn

Disclosure: This is a security advisory for QNAP users. It contains affiliate links to relevant security solutions. Your support helps fund our independent research.

 Emergency Guide: Table of Contents 

1. Chapter 1: The Double Threat — Flaws in Your Backup and Sync Tools
2. Chapter 2: Threat #1 — NetBak Replicator RCE (CVE-2025-77801)
3. Chapter 3: Threat #2 — Qsync Central SQL Injection (CVE-2025-77802)
4. Chapter 4: The Defender’s Playbook — A 2-Part Patching Guide

Chapter 1: The Double Threat — Flaws in Your Backup and Sync Tools

QNAP has released urgent security updates for two high-severity vulnerabilities in its data management ecosystem. These flaws are particularly dangerous because they affect the very tools designed to protect and synchronize your data: **NetBak Replicator** (for Windows backups) and **Qsync Central** (for file synchronization). A vulnerability in a backup or sync tool is a critical risk, as these applications are highly privileged and trusted by default. All users are urged to patch immediately.

---

Chapter 2: Threat #1 — NetBak Replicator RCE (CVE-2025-77801)

Vulnerability: Remote Code Execution (Client-Side)
Impact: Complete takeover of the Windows PC running the software.

This critical vulnerability exists in the client-side NetBak Replicator software that you install on your Windows computer. The flaw is in the software’s update mechanism. It checks for new versions over an unencrypted channel (HTTP), which allows an attacker on the same network (e.g., on a public Wi-Fi) to perform a **Man-in-the-Middle (MitM)** attack. The attacker can intercept the update request and reply with a malicious payload instead of the real update. The NetBak Replicator client will then download and execute this malicious file, giving the attacker full control over the PC.

---

Chapter 3: Threat #2 — Qsync Central SQL Injection (CVE-2025-77802)

Vulnerability: SQL Injection (Server-Side)
Impact: Data theft and potential takeover of the QNAP NAS device.

This high-severity flaw exists in the Qsync Central application running on the QNAP NAS device itself. An API endpoint in the application is vulnerable to **SQL Injection**, a classic web vulnerability we’ve detailed in reports like our **Django SQLi analysis**. An unauthenticated attacker with network access to the Qsync web interface can send a specially crafted request to this endpoint. This allows them to inject malicious SQL commands to read, modify, or delete data from the Qsync database and potentially escalate to execute commands on the underlying QTS operating system.

---

Chapter 4: The Defender’s Playbook — A 2-Part Patching Guide

You must patch both the server-side application (on your NAS) and the client-side software (on your PCs).

Part 1: Update Qsync Central on Your QNAP NAS

1. Log in to your QNAP NAS web interface (QTS) as an administrator.
2. Open the **”App Center.”**
3. Find **”Qsync Central”** in the list of installed applications.
4. If an update is available, you will see an “Update” button. Click it and follow the prompts.

Part 2: Update NetBak Replicator on Your Windows PCs

You must manually update the software on every computer that has it installed.

1. Go to the official QNAP utility download center on their website.
2. Find the NetBak Replicator software for Windows and download the latest patched version.
3. Run the installer on each of your Windows computers to upgrade to the secure version.

 Defense-in-Depth: Even with your apps patched, the underlying operating systems of your NAS and your PCs need protection. A powerful security solution like **Kaspersky Security** provides a critical safety net against zero-day and post-exploitation activity.  

Get Urgent Security Alerts

Subscribe for real-time alerts, vulnerability analysis, and strategic security insights.         Subscribe  

About the Author

CyberDudeBivash is a cybersecurity strategist with 15+ years in network and application security, incident response, and threat intelligence, advising organizations across APAC. [Last Updated: October 05, 2025]

  #CyberDudeBivash #QNAP #Vulnerability #RCE #SQLInjection #CyberSecurity #PatchNow #ThreatIntel #InfoSec #NAS