CVE-2025-47211 Overview
CVE-2025-47211 is a path traversal vulnerability [CWE-22] affecting multiple versions of QNAP QTS and QuTS hero operating systems. An authenticated remote attacker holding administrator credentials can traverse the file system to read the contents of unexpected files or system data outside the intended directory scope.
QNAP has released fixes in QTS 5.2.6.3195 build 20250715 and later, and QuTS hero h5.2.6.3195 build 20250715 and later. The flaw requires high privileges, which limits mass exploitation but expands post-compromise data exposure on NAS appliances.
Critical Impact
Authenticated administrators can read arbitrary files on affected QNAP NAS appliances, exposing configuration data, credentials stored on disk, and potentially sensitive user content.
Affected Products
- QNAP QTS versions prior to 5.2.6.3195 build 20250715
- QNAP QuTS hero versions prior to h5.2.6.3195 build 20250715
- All QNAP NAS appliances running vulnerable QTS or QuTS hero firmware
Discovery Timeline
- 2025-10-03 - CVE-2025-47211 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-47211
Vulnerability Analysis
The vulnerability is a path traversal weakness in QTS and QuTS hero that allows an authenticated administrator to escape an intended directory and reference files elsewhere in the filesystem. Because the affected code path executes with high privileges on the NAS, successful traversal can expose operating system files, application configuration, and user-owned data mounted on the appliance.
Exploitation requires an existing administrator account, which raises the barrier for external attackers but does not eliminate risk. Compromised admin credentials, insider misuse, or chaining with an authentication bypass would all allow arbitrary file reads through this weakness.
The QNAP advisory characterizes the impact as disclosure of unexpected file contents and system data. Integrity and availability are not directly affected, but disclosed contents such as credential files or private keys can enable follow-on attacks.
Root Cause
The root cause is insufficient validation of user-supplied path input, allowing traversal sequences such as ../ to resolve outside of an allowed base directory. QNAP has not published the specific parameter or endpoint affected. Details are limited to the QNAP Security Advisory QSA-25-36.
Attack Vector
The attack vector is network-based. An attacker authenticated as an administrator submits crafted requests to a vulnerable QTS or QuTS hero interface that accept a filename or path parameter. By injecting directory traversal sequences, the attacker forces the server to read files outside the intended location and return their contents in the response.
No public proof-of-concept exploit code is available at the time of publication. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. See the QNAP Security Advisory QSA-25-36 for vendor guidance.
Detection Methods for CVE-2025-47211
Indicators of Compromise
- HTTP requests to QTS or QuTS hero administrative endpoints containing traversal sequences such as ../, ..%2f, or encoded variants in path or filename parameters
- Access log entries showing administrator-authenticated requests returning file contents outside expected application directories
- Unexpected reads of sensitive files such as /etc/shadow, /etc/config/, or private key material by the web application user
Detection Strategies
- Review QNAP web management access logs for anomalous parameter values containing path traversal patterns
- Correlate administrator authentication events with subsequent file-read behavior to identify credential misuse
- Alert on administrative sessions originating from unfamiliar IP addresses or geographies
Monitoring Recommendations
- Forward NAS system and web access logs to a centralized SIEM for retention and correlation
- Monitor for creation or export of unusually large archives that could indicate bulk data exfiltration following a file read
- Track administrator account activity and enable notification for privileged logins
How to Mitigate CVE-2025-47211
Immediate Actions Required
- Upgrade QTS to 5.2.6.3195 build 20250715 or later
- Upgrade QuTS hero to h5.2.6.3195 build 20250715 or later
- Rotate administrator credentials and any secrets that may have been stored on the appliance
- Restrict administrative interface exposure to trusted networks only
Patch Information
QNAP has released fixed firmware in QTS 5.2.6.3195 build 20250715 and QuTS hero h5.2.6.3195 build 20250715. Administrators can apply updates through the Control Panel by navigating to System > Firmware Update and selecting Live Update. Full details are documented in the QNAP Security Advisory QSA-25-36.
Workarounds
- Limit administrator account access to a minimal set of trusted users and enforce strong, unique passwords
- Enable two-factor authentication for all administrator accounts on the NAS
- Place the NAS behind a VPN or firewall rule set that blocks direct exposure of the management interface to the internet
- Enable QNAP's built-in access protection features such as IP allowlisting and account lockout policies
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
