QTS: Stack-based Buffer Overflow
CVE-2025-66280 is a high-severity stack-based buffer overflow vulnerability in QTS from QNAP, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. The record lists version 5.2.9.3410 build 20260214 as the first without the flaw, so updating QTS to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.44% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update QTS to 5.2.9.3410 build 20260214 or a later version.
- Update QuTS hero to h5.2.9.3410 build 20260214 or h5.3.4.3500 build 20260520 or h6.0.0.3397 build 20260206, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| QNAP | QTS | 5.2.0 up to, but not including, 5.2.9.3410 build 20260214 | 5.2.9.3410 build 20260214 |
| QNAP | QuTS hero | h5.2.0 up to, but not including, h5.2.9.3410 build 20260214; h5.3.0 up to, but not including, h5.3.4.3500 build 20260520; ? up to, but not including, h6.0.0.3397 build 20260206 | h5.2.9.3410 build 20260214, h5.3.4.3500 build 20260520, h6.0.0.3397 build 20260206 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- HighAdministrator-level access is required first.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 5.1 | Medium | CNA (qnapsecurity.com.tw) |
| CVSS 3.1 | 7.2 | High | NVD |
Official description
An integer overflow or wraparound vulnerability has been reported to affect several QNAP operating system versions. If a remote attacker gains an administrator account, they can then exploit the vulnerability to compromise the security of the system. We have already fixed the vulnerability in the following versions: QTS 5.2.9.3410 build 20260214 and later QuTS hero h5.2.9.3410 build 20260214 and later QuTS hero h5.3.4.3500 build 20260520 and later QuTS hero h6.0.0.3397 build 20260206 and later
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Stack-based Buffer Overflow
The product writes past the end of a buffer that was allocated on the stack.
How developers prevent this class of flaw
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Implement and perform bounds checking on input.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
Other vulnerabilities in QTS
- 7.2 High severity
- 7.2 High severity
- 7.2 High severity
- 7.2 High severity
- 7.2 High severity
- 7.2 High severity
Recent Stack-based Buffer Overflow vulnerabilities
- 8.2 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 8.1 High severity
- 8.7 High severity
- 7.8 High severity
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