CVE-2025-30276
Published: 11 February 2026
Summary
CVE-2025-30276 is a medium-severity Out-of-bounds Write (CWE-787) vulnerability in Qnap Qsync Central. Its CVSS base score is 4.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 39.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2025-30276 is an out-of-bounds write vulnerability (CWE-787) affecting Qsync Central. Published on 2026-02-11, it carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high severity due to its potential for significant impacts across confidentiality, integrity, and availability.
A remote attacker who has gained a user account can exploit the vulnerability over the network with low complexity and no user interaction required. Successful exploitation allows the attacker to modify or corrupt memory on the affected system.
QNAP has fixed the vulnerability in Qsync Central version 5.0.0.4, released on 2026/01/20, and all later versions. Additional details are available in the vendor's security advisory at https://www.qnap.com/en/security-advisory/qsa-26-02.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-207454
Vulnerability details
An out-of-bounds write vulnerability has been reported to affect Qsync Central. If a remote attacker gains a user account, they can then exploit the vulnerability to modify or corrupt memory. We have already fixed the vulnerability in the following version:…
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Qsync Central 5.0.0.4 ( 2026/01/20 ) and later
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Out-of-bounds write in remotely accessible Qsync Central service directly enables remote exploitation of a public-facing application by an authenticated attacker.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Implements memory protection mechanisms that directly prevent out-of-bounds writes from modifying or corrupting memory as exploited in this CVE.
Enforces input validation to reject malformed data that could trigger the out-of-bounds write vulnerability in Qsync Central.
Requires timely remediation of the specific out-of-bounds write flaw via patching to Qsync Central 5.0.0.4 or later.