QNAP OS XSS and Buffer Overflow

Cross-site scripting in QNAP QTS and QuTS hero operating systems allows remote attackers to bypass security mechanisms and read application data when an authenticated user interacts with attacker-supplied content. The flaw carries a CVSS 4.0 score of 8.7 driven by network reachability, low attack complexity, no required privileges, and high impact across confidentiality, integrity, and availability of the NAS management surface. There is no public exploit identified at time of analysis and the vulnerability is not listed in CISA KEV.

Stack-based buffer overflow in QNAP QTS and QuTS hero NAS operating systems enables an authenticated administrator to corrupt stack memory or crash processes via a network-accessible attack path. Affected versions span QTS 5.2.x and multiple QuTS hero release trains (h5.2.x, h5.3.x, h6.0.x), with vendor-released patches dated February-May 2026. No public exploit code and no CISA KEV listing have been identified at time of analysis, and the mandatory high-privilege prerequisite substantially limits realistic attack surface.