CVE-2025-53409: QNAP Systems File Station 5 · Unthrottled Resource Allocation
Affects QNAP Systems File Station 5Source CVE Database V5
Not known to be exploited · CVSS 4.9 Medium : upgrade to 5.6.0 when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.6.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:UExploitation evidence
Disclosed: evidence found.
CVE published 7 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade QNAP Systems File Station 5 to 5.6.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| QNAP Systems Inc. File Station 5 | Affected
| Fixed in
|
AI-suggested
To mitigate CVE-2025-53409, European organizations should: 1) Immediately upgrade all QNAP NAS devices running File Station 5 to version 5.5.6.5018 or later, where the vulnerability is patched. 2) Implement strict user account management policies, including strong authentication mechanisms, regular credential audits, and timely revocation of unused or compromised accounts to reduce the risk of attacker access. 3) Monitor resource usage metrics on NAS devices to detect unusual spikes indicative of resource exhaustion attempts. 4) Employ network segmentation and access controls to limit exposure of NAS management interfaces to trusted networks and users only. 5) Consider deploying anomaly detection tools that can alert on abnormal file access patterns or resource consumption. 6) Maintain up-to-date backups and incident response plans to minimize operational impact in case of exploitation. These measures go beyond generic advice by focusing on both patching and operational controls tailored to the nature of the vulnerability and the environment.
Description
An allocation of resources without limits or throttling vulnerability has been reported to affect File Station 5. If a remote attacker gains a user account, they can then exploit the vulnerability to prevent other systems, applications, or processes from accessing the same type of resource. We have already fixed the vulnerability in the following version: File Station 5 5.5.6.5018 and later