CVE-2026-26240
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 · uneditedA buffer overflow vulnerability has been reported to affect File Station 5. The remote attackers can then exploit the vulnerability to modify memory or crash processes. We have already fixed the vulnerability in the following version: File Station 5 5.5.6.5243 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 · high confidenceA buffer overflow vulnerability in QNAP File Station 5 allows remote attackers to overflow a buffer via crafted input, potentially enabling arbitrary memory modification or denial-of-service via process crash.
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>= 5.5.6.4691, < 5.5.6.5243CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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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Confirm File Station 5 is installedAccess the QNAP device via the web interface (QTS) and navigate to App Center, or use the command line to list installed packages (qpkg command if available). Look for an entry named 'File Station' or 'File Station 5'.Affected if File Station 5 is present on the system
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Retrieve the installed version of File Station 5In the QTS web interface, go to App Center, find File Station, and note the version number displayed. Alternatively, use the command 'qpkg -i | grep -i file station' to retrieve version information via SSH.Affected if A version number is returned for File Station 5
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Compare version against vulnerable rangeExamine the installed version number (e.g., 5.5.6.4691) and determine if it falls within the affected range: any version greater than or equal to 5.5.6.4691 and less than 5.5.6.5243.Affected if The installed version is >= 5.5.6.4691 and < 5.5.6.5243
The system is affected if QNAP File Station 5 is installed with a version between 5.5.6.4691 and 5.5.6.5242 inclusive.
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 · scoped5.5.6.5243
Upgrade File Station 5 to version 5.5.6.5243 or later to apply the vendor patch. If immediate patching is not possible, consider network segmentation to limit exposure to untrusted users.
File Station 5.5.6.5243
- Check the current File Station version installed on the QNAP NAS
- Access the QNAP App Center or File Station update mechanism
- Locate File Station in the available updates
- Upgrade to File Station version 5.5.6.5243 or later
- Verify the upgrade was successful by checking the updated version number
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-26240 — 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-2026-26240 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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