CVE-2025-29890: Qnap File Station 5 DoS Vulnerability

CVE-2025-29890 Overview

CVE-2025-29890 is a resource allocation vulnerability affecting QNAP File Station 5. The flaw stems from allocation of resources without limits or throttling [CWE-770]. A remote attacker who obtains a valid user account can exhaust shared resources, preventing other systems, applications, or processes from accessing the same resource type. QNAP addressed the issue in File Station 5 version 5.5.6.4907 and later. The vulnerability was published to the National Vulnerability Database (NVD) on August 29, 2025.

Critical Impact
Authenticated remote attackers can trigger resource exhaustion in QNAP File Station 5, denying service availability to legitimate users and dependent processes on the NAS.

Affected Products

QNAP File Station 5 versions prior to 5.5.6.4907
QNAP NAS deployments running vulnerable File Station 5 packages
Network-attached storage environments exposing File Station to authenticated users

Discovery Timeline

2025-08-29 - CVE-2025-29890 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-29890

Vulnerability Analysis

CVE-2025-29890 is categorized as a resource exhaustion issue mapped to [CWE-770], "Allocation of Resources Without Limits or Throttling." File Station 5 accepts requests from authenticated users without enforcing sufficient bounds on the resources those requests consume. An attacker with a low-privilege account can repeatedly invoke resource-consuming operations to starve the underlying service.

When the resource pool is exhausted, other users, applications, and background processes that depend on the same resource type cannot proceed. This produces a denial-of-service condition scoped to File Station and related NAS functionality. The vulnerability requires network access and authentication but no user interaction.

Root Cause

The root cause is the absence of quotas, rate limits, or throttling on resource-allocating operations in File Station 5. QNAP fixed the issue in File Station 5 5.5.6.4907 per QNAP Security Advisory QSA-25-19.

Attack Vector

Exploitation requires network reachability to the File Station 5 service and possession of a valid user account. The attacker issues repeated or malformed requests against resource-allocating endpoints until availability degrades. No user interaction is required and the attack complexity is low.

No public proof-of-concept or exploit code is available at time of publication, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. Refer to the vendor advisory for exploitation constraints and remediation details.

Detection Methods for CVE-2025-29890

Indicators of Compromise

Sustained spikes in CPU, memory, or file-descriptor usage on QNAP NAS devices tied to the File Station process
Repeated authenticated File Station API requests originating from a single account or source IP
File Station service errors, timeouts, or unresponsiveness reported by legitimate users
QNAP system logs recording aborted sessions or resource allocation failures

Detection Strategies

Monitor File Station 5 request patterns for anomalous request volume from individual accounts
Correlate NAS resource utilization metrics with authentication logs to identify abusive sessions
Alert on repeated failed or long-running File Station operations tied to the same user identity

Monitoring Recommendations

Forward QNAP system and application logs to a centralized logging platform for correlation
Track baseline resource utilization on NAS devices and alert on sustained deviations
Review File Station account activity for accounts with unexpected usage patterns or geographic origins

How to Mitigate CVE-2025-29890

Immediate Actions Required

Upgrade File Station 5 to version 5.5.6.4907 or later on all QNAP NAS devices
Audit File Station user accounts and disable accounts that are unused, shared, or over-privileged
Restrict File Station network exposure to trusted networks and VPN-reachable clients only
Enforce strong authentication, including multi-factor authentication, on all NAS user accounts

Patch Information

QNAP released a fix in File Station 5 5.5.6.4907 and later. Administrators should install the update through the QNAP App Center or QTS/QuTS hero update workflow. Full remediation guidance is available in QNAP Security Advisory QSA-25-19.

Workarounds

Limit File Station access to a minimal set of authenticated users until the patch is applied
Place NAS management interfaces behind a VPN or firewall rule set that blocks internet exposure
Apply per-account rate limits at an upstream reverse proxy or firewall where feasible
Monitor NAS resource utilization and terminate abusive sessions promptly

bash

# Verify installed File Station version on a QNAP NAS (SSH)
qpkg_cli --list | grep -i "File Station"

# After update, confirm version is 5.5.6.4907 or later