CVE-2025-66280: qnap systems inc. qts Stack-based Buffer Overflow

Vulnerability summary

CVE-2025-66280 is a high (CVSS 7.2) Stack-based Buffer Overflow vulnerability in qnap systems inc. qts. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 36.7% of scored vulnerabilities.

Timeline

1. 10-06-2026
   PublishedVulnerability first disclosed.
2. 10-06-2026
   Last modifiedVulnerability information updated.

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

• CWE-121Stack-based Buffer OverflowA stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
• CWE-190Integer Overflow or WraparoundThe 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 occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.