# CVE-2025-66280 — QNAP Systems Inc. QTS > As of 2026-06-10, CVE-2025-66280 is a HIGH-severity vulnerability in QNAP Systems Inc. QTS, CVSS v3.1 7.2, EPSS 0.3% (24.6th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2025-66280, most recently “QNAP QSA-26-10: Multiple Injection and Memory-Safety Vulnerabilities in QTS, QuTS hero, QuTS cloud, QVP, and File Station (CVE-2025-66273, CVE-2026-26240, and 12 others)”. **Last updated:** 2026-06-10 ## What is CVE-2025-66280? 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 record classifies CVE-2025-66280 under weakness classes [CWE-190](https://cwe.mitre.org/data/definitions/190.html), [CWE-121](https://cwe.mitre.org/data/definitions/121.html). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs high-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 94 days ago. ## Severity and exploitation probability - **CVSS v3.1 base score:** 7.2 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`) - **CVSS v4.0 base score:** 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N`) - **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 24.6% of all scored CVEs - **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog - **Threadlinqs priority:** 4.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability - **Published:** 2026-06-10 ## Is CVE-2025-66280 being exploited? No public exploitation evidence for CVE-2025-66280 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-06-10. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited. ## Affected products and versions - **QNAP Systems Inc.**: QTS, QuTS hero ## How to fix CVE-2025-66280 Vendor advisory: [https://www.qnap.com/en/security-advisory/qsa-26-10](https://www.qnap.com/en/security-advisory/qsa-26-10). Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory. ## Threat activity tracking CVE-2025-66280 1 tracked threat in the Threadlinqs corpus references CVE-2025-66280, either in the campaign’s CVE list or as an indicator on the campaign record. - [QNAP QSA-26-10: Multiple Injection and Memory-Safety Vulnerabilities in QTS, QuTS hero, QuTS cloud, QVP, and File Station (CVE-2025-66273, CVE-2026-26240, and 12 others)](https://intel.threadlinqs.com/threat/TL-2026-0901) — HIGH · 2026-06-22 ## Sources Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-06-22. This product uses the NVD API but is not endorsed or certified by the NVD. **Other references** - [qnap.com](https://www.qnap.com/en/security-advisory/qsa-26-10) Canonical: https://intel.threadlinqs.com/cve/CVE-2025-66280 Full detection coverage and IOCs for threats exploiting CVE-2025-66280 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp