CVE-2026-26239
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. If a remote attacker gains a user account, they can then exploit the vulnerability to modify memory or crash processes. We have already fixed the vulnerability in the following version: File Station 5 5.5.6.5208 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 authenticated remote attackers to modify memory or crash processes. The attacker requires a valid user account before exploitation, making this an authenticated attack vector with high severity due to potential memory corruption.
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, < 5.5.6.5208CVSS 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
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/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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Verify File Station 5 is installedAccess QNAP NAS admin panel, go to App Center or QNAP Store, and check installed applications for File Station 5Affected if File Station 5 is not installed or only File Station 6 is present - not affected
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Determine installed File Station 5 versionIn QNAP admin panel, open File Station 5, click the menu icon (three lines) > Help > About, or check QNAP App Center for the installed version numberAffected if Version is 5.5.6.4691 through 5.5.6.5207 (inclusive) - vulnerable
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Confirm version is in affected rangeCompare your installed version against the vulnerable range: >= 5.5.6.4691 and < 5.5.6.5208Affected if Version starts with 5.5.6.4691, 5.5.6.4700, 5.5.6.4800, 5.5.6.4900, 5.5.6.5000, 5.5.6.5100, or 5.5.6.5200 through 5.5.6.5207 - vulnerable
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Check if File Station 5 is network accessibleVerify that File Station 5 web interface or associated ports are exposed to network users (typically port 5000/5001 or custom QNAP web ports)Affected if File Station 5 is accessible over network AND version is in vulnerable range - at risk
You are affected only if File Station 5 is installed AND its version falls between 5.5.6.4691 and 5.5.6.5207 inclusive, and the service is accessible to users.
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 · scoped5.5.6.5208
Upgrade File Station 5 to version 5.5.6.5208 or later. Since the vulnerability requires authentication, ensure strong credential policies and monitor for unauthorized account creation.
File Station 5 version 5.5.6.5208 or later
- Log into the QNAP NAS web interface as an administrator
- Navigate to App Center or the File Station application
- Check the current File Station version (should be >= 5.5.6.4691 and < 5.5.6.5208)
- Locate File Station in the available updates
- Update File Station to version 5.5.6.5208 or later
- Verify the update was successful by checking the File Station version after updating
- Ensure the update completes without errors
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-26239 — 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-2026-26239 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data