CVE-2021-20686
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 vulnerability in Kagemai 0.8.8 allows remote attackers to inject an arbitrary script via unspecified vectors.
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 confidenceKagemai 0.8.8 contains a cross-site scripting (XSS) vulnerability allowing remote attackers to inject arbitrary JavaScript or HTML into web pages viewed by other users. The vulnerability stems from insufficient input validation and output encoding of user-supplied data within the bug tracking application.
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= 0.8.8CVSS 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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Locate Kagemai installation directorySearch the server filesystem for the Kagemai application directory, typically found in web server document roots (e.g., /var/www/html/, /usr/local/apache/htdocs/) or application deployment directories. Look for directories containing 'kagemai' in the name.Affected if Kagemai is installed on the server
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Identify installed Kagemai versionCheck the version file or script within the Kagemai installation. Common locations include a VERSION file, version.pm module, or the main script header. Open the file and read the version string.Affected if The version returned is exactly 0.8.8
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Confirm bug submission functionality is activeVerify that the bug tracking application is accessible and the user-submitted bug report form is functional. Check if the application accepts input via HTTP POST requests to the bug submission handler.Affected if The bug submission feature is accessible and accepts user input without sanitization verification
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Inspect user input handling for output encodingExamine the Kagemai source code, specifically the input handling and template rendering scripts. Look for places where user-submitted data (bug title, description, comments) is inserted into HTML output without proper encoding functions.Affected if User input data is rendered in HTML responses without sanitization or encoding functions applied
A system is affected if Daifukuya Kagemai version 0.8.8 is running and the bug tracking feature accepts user input that gets displayed without output encoding.
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 dataApply output encoding/sanitization to all user inputs and HTTP responses, implement input validation whitelist where possible, and configure Content-Security-Policy headers to mitigate XSS execution.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20686 — 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-2021-20686 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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