CVE-2020-3939
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 · uneditedSysJust Syuan-Gu-Da-Shih, versions before 20191223, contain vulnerability of Cross-Site Scripting(XSS), personal information may be leaked to attackers via the vulnerability.
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 confidenceSysJust Syuan-Gu-Da-Shih versions before 20191223 contain a Cross-Site Scripting (XSS) vulnerability that allows attackers to inject malicious scripts into the web application, potentially exfiltrating personal information from authenticated users or other visitors.
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< 20191223CVSS 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 the installed version of SysJust Syuan-Gu-Da-ShihLocate the application version information in the system documentation, about page, or application header/footer. Check the software inventory or deployment records if available.Affected if The installed version is any version number lower than 20191223, or if the version cannot be determined but the software was installed before December 23, 2019.
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Confirm the web application interface is active and accessibleAttempt to access the application's web URL or verify that the web service is running and responding to HTTP requests.Affected if The web interface is publicly or internally accessible, as this provides the attack surface for XSS exploitation.
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Determine if user input forms or parameters are acceptedReview the application's available pages, forms, search fields, comment boxes, or any feature that accepts user-supplied data that could be rendered in web pages.Affected if The application accepts and displays user input without evident sanitization, as this is required for the XSS vulnerability to be exploitable.
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Check if authentication or user sessions are enabledVerify whether the application supports user accounts, login functionality, or session management features.Affected if Authenticated users can interact with the application, as the CVE notes personal information exfiltration from authenticated users is a potential impact.
You are affected if the installed version of SysJust Syuan-Gu-Da-Shih is earlier than version 20191223 AND the web application is accessible and accepts user input that could be rendered in pages.
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 data20191223
Implement proper input validation and output encoding for all user-supplied data, applyContent Security Policy headers, and consider deploying a web application firewall to detect and block XSS attacks.
- Consultation2.0 h
- Implementation4.0 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-2020-3939 — 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-2020-3939 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