CVE-2021-31703
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 · uneditedFrontier ichris through 5.18 allows users to upload malicious executable files that might later be downloaded and run by any client user.
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 confidenceInsecure file upload vulnerability in Frontier ichris through version 5.18 allows authenticated users to upload malicious executable files (such as .exe, .php, .bat, .sh) to the server. These files are stored in a manner that allows other client users to download and execute them, potentially leading to remote code execution and complete system compromise.
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<= 5.18CVSS 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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Confirm Ichris installation and versionLocate the Ichris application installation directory and check the version file or metadata. Common locations include /opt/ichris, /var/www/ichris, or the program's internal about/version info. Compare the installed version to the affected range (<= 5.18).Affected if The installed version of Frontier Ichris is 5.18 or lower.
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Verify file upload functionality is enabledAccess the Ichris web interface and navigate to any feature that provides file upload capability (e.g., document management, attachment upload, content import). Confirm the upload feature is accessible to authenticated users.Affected if The file upload feature is enabled and accessible to authenticated user accounts.
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Inspect uploaded file storage locationExamine the server configuration and file storage path where uploaded files are saved. Determine if the upload directory is located within the web server's document root (web-accessible) or outside of it.Affected if Uploaded files are stored in a directory accessible via HTTP/HTTPS (within the web root).
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Check file serving configurationReview the web server configuration (Apache/nginx/IIS) to determine how uploaded files are served. Check if files are delivered with proper Content-Type headers that prevent execution, or if they are served in a way that allows direct execution.Affected if Uploaded files are served without restrictions that prevent execution, and executable file types (.exe, .php, .bat, .sh) can be accessed and run via the web server.
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Test file type validationAttempt to upload a test file with an executable extension (.php, .exe, .bat, .sh) using an authenticated user account. Observe whether the upload is accepted or rejected by the application.Affected if The application accepts and stores executable file types without proper validation or blocking.
A user is affected if they are running Ichris version 5.18 or lower with the file upload feature enabled, and uploaded files are stored in a web-accessible location without execution prevention controls.
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 strict allowlist-based file type validation (both client-side and server-side), store uploaded files outside the web root or in a non-executable manner, serve files with proper Content-Type headers that prevent execution, and rename uploaded files to remove executable extensions.
- 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-2021-31703 — 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-2021-31703 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