CVE-2025-30276
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn 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: Qsync Central 5.0.0.4 ( 2026/01/20 ) and later
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceAn out-of-bounds write vulnerability exists in Qsync Central where a remote attacker with a valid user account can write beyond allocated memory boundaries, leading to memory corruption. This memory corruption could potentially allow modification of program execution flow or denial of service.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 5.0.0.0, < 5.0.0.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Qsync Central versionLog into the Qnap Qsync Central admin interface (usually via https://[device-ip]:[port]/qsync) and navigate to Control Panel > Applications > Qsync Central > About to view the installed version numberAffected if The installed version is 5.0.0.0, 5.0.0.1, 5.0.0.2, or 5.0.0.3 (any version >=5.0.0.0 and <5.0.0.4)
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Confirm Qsync Central web interface is accessibleVerify that the Qsync Central web portal is reachable over the network on typical ports 443 or 8080. Attempt to access the login page from a remote clientAffected if The Qsync Central web interface is exposed to network where untrusted users could reach it
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Review Qsync Central user accountsIn the Qsync Central admin panel, navigate to Users or Account settings to list all user accounts that have access to Qsync CentralAffected if There are user accounts beyond trusted administrators, or accounts accessible to untrusted personnel
If Qsync Central version is 5.0.0.0 through 5.0.0.3 and the web interface is accessible to users with valid accounts, the environment is affected by this vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped5.0.0.4
Upgrade Qsync Central to version 5.0.0.4 or later. Until the upgrade can be applied, limit user account access to trusted personnel only and monitor for anomalous activity.
Qsync Central 5.0.0.4
- Identify the current version of Qsync Central installed on the QNAP NAS
- Navigate to the QNAP App Center or QNAP download center to obtain Qsync Central version 5.0.0.4 or later
- Follow QNAP's standard application update procedure to upgrade Qsync Central to version 5.0.0.4 or newer
- Verify the upgrade was successful by confirming the installed version is 5.0.0.4 or later
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-30276 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-30276 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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