QNAP QTS/QuTS hero 5.2.9.3410/5.3.4.3500/6.0.0.3397 integer overflow

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
3.7	$0-$5k	1.92

Summaryinfo

A vulnerability described as problematic has been identified in QNAP QTS and QuTS hero 5.2.9.3410/5.3.4.3500/6.0.0.3397. This impacts an unknown function. Executing a manipulation can lead to integer overflow. This vulnerability is registered as CVE-2025-66280. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in QNAP QTS and QuTS hero 5.2.9.3410/5.3.4.3500/6.0.0.3397. It has been declared as problematic. This vulnerability affects an unknown code block. The manipulation with an unknown input leads to a integer overflow vulnerability. The CWE definition for the vulnerability is CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. As an impact it is known to affect integrity, and availability. CVE summarizes:

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

The weakness was published by Bechir Bouali as qsa-26-10. The advisory is shared for download at qnap.com. This vulnerability was named CVE-2025-66280 since 11/26/2025. The exploitation appears to be easy. The attack can be initiated remotely. The exploitation requires an enhanced level of successful authentication. There are neither technical details nor an exploit publicly available.

Upgrading eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Network Attached Storage Software

Vendor

QNAP

Name

Version

License

commercial

Website

Vendor: https://www.qnap.com/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 3.8
VulDB Meta Temp Score: 3.7

VulDB Base Score: 3.8
VulDB Temp Score: 3.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Integer overflow
CWE: CWE-190 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Timelineinfo

11/26/2025 CVE reserved
06/10/2026 +195 days Advisory disclosed
06/10/2026 +0 days VulDB entry created
06/10/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: qnap.com

Advisory: qsa-26-10
Researcher: Bechir Bouali
Status: Confirmed

CVE: CVE-2025-66280 (🔒)
GCVE (CVE): GCVE-0-2025-66280
GCVE (VulDB): GCVE-100-370060

Entryinfo

Created: 06/10/2026 06:45
Changes: 06/10/2026 06:45 (67)
Complete: 🔍
Cache ID: 216::103