CVE-2018-8911
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 · uneditedCross-site scripting (XSS) vulnerability in Attachment Preview in Synology Note Station before 2.5.1-0844 allows remote authenticated users to inject arbitrary web script or HTML via malicious attachments.
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 confidenceCross-site scripting (XSS) vulnerability in Synology Note Station's Attachment Preview feature allows authenticated users to inject malicious scripts via crafted attachment files. The vulnerability stems from insufficient sanitization of attachment content when rendering previews, allowing arbitrary HTML/JavaScript execution in the context of other users' browsers.
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< 2.5.1-0844CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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 Note Station is installedAccess Synology DiskStation and open Package Center. Look for Note Station in the installed packages list.Affected if Note Station is not present in the installed packages - the vulnerability does not apply.
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Determine installed Note Station versionIn Package Center, click on Note Station and view the version information displayed. Alternatively, open Note Station application and check About or Version section in the settings.Affected if Unable to confirm the exact version number - further investigation needed.
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Compare version against affected rangeCompare the installed version number to 2.5.1-0844. Note Station versions follow the format major.minor.patch-build (for example, 2.5.0-0833 or 2.5.1-0844).Affected if Installed version is any version earlier than 2.5.1-0844 (e.g., 2.5.0, 2.4.x, etc.) - the version is vulnerable.
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Confirm Attachment Preview is accessibleLog into Note Station as an authenticated user. Navigate to any note that has an attachment and verify the preview feature can be accessed by clicking on the attachment.Affected if Attachment Preview feature is available and users can view attachment previews - the attack surface exists.
User is affected if Note Station is installed with any version lower than 2.5.1-0844 and the Attachment Preview feature is accessible to authenticated 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.
From vendor data2.5.1-0844
Upgrade to Note Station version 2.5.1-0844 or later, which includes proper input sanitization and output encoding for attachment previews.
- Consultation2.0 h
- Implementation4.0 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-2018-8911 — 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-2018-8911 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