CVE-2024-50401: QNAP QTS Information Disclosure Flaw

CVE-2024-50401 Overview

CVE-2024-50401 is an externally-controlled format string vulnerability [CWE-134] affecting multiple versions of QNAP's QTS and QuTS hero operating systems. Remote attackers who have already obtained administrator access can exploit this flaw to read sensitive memory contents or modify process memory. QNAP addressed the issue in QTS 5.2.1.2930 build 20241025 and QuTS hero h5.2.1.2929 build 20241025. The vulnerability requires authenticated administrator privileges, which limits its practical exploitability. QNAP published guidance in security advisory QSA-24-43.

Critical Impact
Authenticated administrators can leverage crafted format string inputs to disclose secret data from process memory or overwrite memory regions on affected QNAP NAS devices.

Affected Products

QNAP QTS versions prior to 5.2.1.2930 build 20241025
QNAP QuTS hero versions prior to h5.2.1.2929 build 20241025
Confirmed affected builds include QTS 5.2.0.2737 through 5.2.0.2860 and QuTS hero h5.2.0.2737 through h5.2.0.2860

Discovery Timeline

2024-11-22 - CVE-2024-50401 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-50401

Vulnerability Analysis

The flaw is a classic use of an externally-controlled format string, categorized under [CWE-134]. An application component in QTS and QuTS hero passes attacker-influenced input directly into a formatted output function without first sanitizing or constraining the format specifiers. Because format specifiers such as %s, %x, and %n are interpreted by the underlying printf-family routines, attacker-supplied specifiers change how the function reads from or writes to memory. Exploitation is constrained by the requirement that the attacker already hold administrator credentials on the target NAS. Successful use produces information disclosure of process memory or modification of memory values, depending on the specifiers supplied.

Root Cause

The root cause is improper handling of user-supplied strings that are forwarded into format-string-aware APIs. When a program uses input as the format argument rather than as a formatted value, each % token in that input drives a memory read or write against the current stack frame or a supplied pointer. QNAP's advisory QSA-24-43 confirms that affected components were rebuilt to remove attacker control over the format argument in the fixed builds.

Attack Vector

The attack vector is network-based but requires prior authentication as an administrator on the QTS or QuTS hero web management interface or associated services. An attacker with valid administrator credentials submits crafted input containing format specifiers to a vulnerable parameter. Depending on how the target function is invoked, the attacker can read adjacent stack values, leak pointer or credential data, or write attacker-chosen values into memory via %n-style specifiers.

No verified public exploit code or proof-of-concept has been published for this issue. See the QNAP Security Advisory QSA-24-43 for vendor detail.

Detection Methods for CVE-2024-50401

Indicators of Compromise

Administrative session activity from unexpected geolocations or IP ranges immediately preceding anomalous NAS behavior
QTS or QuTS hero service crashes, restarts, or segmentation faults recorded in system logs
HTTP request bodies or query parameters submitted by administrator accounts containing repeated %s, %x, %p, or %n sequences

Detection Strategies

Inspect QNAP system and web server logs for administrator requests containing format specifier patterns in URL parameters, headers, or POST bodies
Correlate administrator login events with subsequent process crashes or unexpected memory access errors on the appliance
Compare running QTS or QuTS hero build strings against the fixed builds 5.2.1.2930 and h5.2.1.2929 to identify unpatched devices

Monitoring Recommendations

Forward QNAP syslog output to a centralized SIEM and alert on repeated administrator authentication followed by service faults
Enable auditing of administrative configuration changes and monitor for out-of-hours administrator activity
Restrict management interface exposure to trusted management networks and log all access attempts

How to Mitigate CVE-2024-50401

Immediate Actions Required

Upgrade QTS installations to 5.2.1.2930 build 20241025 or later
Upgrade QuTS hero installations to h5.2.1.2929 build 20241025 or later
Audit administrator accounts, remove unused privileged users, and rotate credentials on devices that were exposed to untrusted networks
Remove direct internet exposure of the QNAP management interface and place it behind a VPN or firewall access control list

Patch Information

QNAP released fixed firmware in QTS 5.2.1.2930 build 20241025 and QuTS hero h5.2.1.2929 build 20241025. Patches can be applied through the QNAP Control Panel under System > Firmware Update or by downloading the firmware image from QNAP's download center. Refer to the QNAP Security Advisory QSA-24-43 for the authoritative fix list.

Workarounds

Limit administrator account membership and enforce multi-factor authentication on all administrative accounts
Restrict access to the QTS and QuTS hero management interfaces to trusted internal networks or VPN clients
Disable remote administrator access features such as myQNAPcloud Link where not strictly required until the firmware update is applied

bash

# Verify current firmware build on a QNAP appliance via SSH
getcfg System Version -f /etc/config/uLinux.conf
getcfg System "Build Number" -f /etc/config/uLinux.conf

# Compare output against fixed builds:
#   QTS       >= 5.2.1.2930 build 20241025
#   QuTS hero >= h5.2.1.2929 build 20241025