CVE-2021-20721
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 · uneditedKonaWiki2 versions prior to 2.2.4 allows a remote attacker to upload arbitrary files via unspecified vectors. If the file contains PHP scripts, arbitrary code may be executed.
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 confidenceKonaWiki2 versions before 2.2.4 contains an arbitrary file upload vulnerability allowing unauthenticated remote attackers to upload any file type to the server. If the uploaded file contains PHP code, the attacker can achieve remote code execution by requesting the uploaded file.
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< 2.2.4CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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 installed KonaWiki2 versionLocate the version file or admin panel that displays the KonaWiki2 version number, typically found in the application header, about page, or version configuration fileAffected if The installed version is lower than 2.2.4
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Verify file upload functionality is presentAccess the wiki and look for file upload options, typically found in page editing tools, attachments section, or a dedicated upload interfaceAffected if File upload functionality exists and is accessible to users
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Check if upload endpoint allows unauthenticated accessAttempt to access the file upload script/endpoint without logging in - common paths include /index.php with upload action, /attach/, or similar upload-related URLsAffected if The upload endpoint accepts requests without requiring authentication
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Confirm uploaded files are web-accessibleAfter uploading a test file (or reviewing upload configuration), verify the files are stored in a web-accessible directory and can be requested via HTTPAffected if Uploaded files are stored in a web-accessible directory and can be directly requested via browser or curl
You are affected if running KonaWiki2 version below 2.2.4 AND file upload functionality is enabled and accessible without authentication, allowing attackers to upload executable files to a web-accessible location.
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.
dbcve · scoped2.2.4
Upgrade to KonaWiki2 version 2.2.4 or later. If immediate upgrade is not feasible, disable file upload functionality and/or implement server-side restrictions on file types (whitelist approach) to prevent executable files from being stored.
2.2.4
- Confirm current installed version of KonaWiki2
- Download KonaWiki2 version 2.2.4 from the official source (kujirahand.com)
- Back up the existing database and all wiki files
- Replace existing files with the new version 2.2.4 files
- Verify the upgrade was successful by checking the version number in the admin interface
- Test file upload functionality to confirm the vulnerability is patched
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 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 $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20721 — 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-2021-20721 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