CVE-2020-5195
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 · uneditedReflected XSS through an IMG element in Cerberus FTP Server prior to versions 11.0.1 and 10.0.17 allows a remote attacker to execute arbitrary JavaScript or HTML via a crafted public folder URL. This occurs because of the folder_up.png IMG element not properly sanitizing user-inserted directory paths. The path modification must be done on a publicly shared folder for a remote attacker to insert arbitrary JavaScript or HTML. The vulnerability impacts anyone who clicks the malicious link crafted by the attacker.
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 confidenceReflected XSS in Cerberus FTP Server's web interface where the folder_up.png IMG element fails to sanitize user-supplied directory paths in publicly shared folder URLs, allowing attackers to inject arbitrary JavaScript/HTML via crafted URLs.
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>= 10.0.0, < 10.0.17>= 11.0.0, < 11.0.1CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/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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Identify Cerberus FTP Server installation and versionCheck the Windows installed programs list, or look for Cerberus FTP Server in Program Files, or check the service name in Windows Services. The version is typically displayed in the application GUI or can be found in the program's About/Help section.Affected if The installed version falls within 10.0.0 to 10.0.16 or 11.0.0
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Verify the web interface is enabledAccess the Cerberus FTP Server administration interface, typically at https://localhost:9090 or http://localhost:8080, and check if the web server is running. Alternatively, check the Cerberus service configuration for HTTP/HTTPS listener ports.Affected if The web interface HTTP/HTTPS listeners are active and accessible
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Confirm publicly shared folders existIn the Cerberus administration interface, navigate to the Sharing or Public Folders section and check if any folders are configured for public (anonymous) access.Affected if Public or anonymous-access shared folders are configured in the FTP server
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Test for reflected XSS in shared folder URLAccess a shared folder URL and observe if the directory path parameter is reflected in the page source without proper encoding. For example, if a shared folder link contains a path parameter, modify it to include a test string like <script>alert(1)</script> and check if it executes or appears unescaped in the HTML.Affected if User-supplied directory path values are reflected in the web page without HTML encoding
A user is affected if Cerberus FTP Server version 10.0.0-10.0.16 or 11.0.0 is installed with the web interface enabled and publicly shared folders configured, allowing reflected XSS via crafted shared folder URLs.
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 data10.0.1711.0.1
Upgrade to Cerberus FTP Server version 11.0.1 or 10.0.17 or later which contains proper input sanitization for directory path parameters.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-5195 — 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-2020-5195 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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