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CVE-2025-30276VulnerabilityPublished

CVE-2025-30276: QNAP Systems Qsync Central · CWE-787

Affects QNAP Systems Qsync CentralSource CVE Database V5

0

Not known to be exploited · CVSS 4.9 Medium : upgrade to 5.0.0.4 ( 2026/01/20 ) when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score
4.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.0.0.4 ( 2026/01/20 )
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 11 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

Upgrade QNAP Systems Qsync Central to 5.0.0.4 ( 2026/01/20 ).

Affected software

ProductAffectedFixed in
QNAP Systems Inc.Qsync CentralAffected
  • =5.0.x.x
Fixed in
  • 5.0.0.4 ( 2026/01/20 )

AI-suggested

European organizations should immediately upgrade Qsync Central installations to version 5.0.0.4 or later to remediate this vulnerability. Beyond patching, organizations should enforce strict user account management policies, including strong password requirements, multi-factor authentication, and least privilege principles to reduce the risk of compromised credentials. Network segmentation and firewall rules should limit access to Qsync Central services to trusted hosts and networks. Regular monitoring and logging of user activities on Qsync Central can help detect anomalous behavior indicative of exploitation attempts. Additionally, organizations should conduct periodic vulnerability assessments and penetration testing focused on NAS devices and synchronization services. Backup strategies should be reviewed to ensure data integrity and availability in case of service disruption.

Description

CVE-2025-30276 is an out-of-bounds write vulnerability in QNAP Systems Inc. 's Qsync Central version 5.0.x.x. A remote attacker with a valid user account can exploit this flaw to corrupt or modify memory, potentially leading to system instability or unauthorized behavior. The vulnerability does not require user interaction and has a medium severity with a CVSS score of 4.9. It was fixed in Qsync Central version 5.0.

References

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