CVE-2021-30086
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 exists in KindEditor (Chinese versions) 4.1.12, which can be exploited by an attacker to obtain user cookie information.
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 confidenceCross Site Scripting (XSS) vulnerability in KindEditor 4.1.12 allows attackers to inject malicious scripts into web pages served by the editor, enabling theft of user cookie information through script execution in victim 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= 4.1.12CVSS 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.
-
Locate KindEditor installation filesSearch the web server file system for KindEditor components such as kindeditor.js, kindeditor-min.js, or the kindeditor directory. Check common web application directories like /js/, /lib/, /plugins/, or application-specific paths where third-party editors are stored.Affected if KindEditor files are found in the environment
-
Identify the KindEditor versionOpen the main JavaScript file (kindeditor.js or kindeditor-min.js) in a text editor and locate the version declaration. This is typically found in a comment header, a version variable, or metadata at the top of the file.Affected if The version cannot be determined or the file is not found
-
Compare installed version to affected releaseIf the version is found, verify whether it is exactly 4.1.12. The affected version is denoted by the equals sign (=) in the advisory, meaning only version 4.1.12 is vulnerable.Affected if The installed version is 4.1.12
-
Determine if KindEditor renders user-supplied contentReview how KindEditor is integrated into the application. Identify whether the editor is used to display or render content that originates from user input, as this is required for the XSS to be exploitable.Affected if KindEditor processes and displays user input in web pages
The environment is affected if KindEditor version 4.1.12 is installed and configured to render user-supplied content in web 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 dataImplement proper input validation and output encoding on all user-supplied content rendered by KindEditor, or upgrade to a patched version if available. Additionally, configure cookie security flags (HttpOnly, Secure) to prevent cookie theft even if XSS exists.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30086 — 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-2021-30086 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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