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Unrestricted File UploadWeakness · CWE-434

CVE-2026-34735

HIGH · 8.7 CVSS v4.0 Published 2026-04-02
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
93/100
Remediation priority · Urgent
Remotely reachable Zero-click

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 · unedited
The Hytale Modding Wiki is a free service for Hytale mods to host their documentation & wikis. In version 1.2.0 and prior, the quickUpload() endpoint validates uploaded files by checking their MIME type (via PHP's finfo, which inspects file contents) but constructs the stored filename using the client-supplied file extension from getClientOriginalExtension(). These two checks are independent: an attacker can upload a file whose content passes the MIME allowlist while using a .php extension. The file is stored on the public disk and is directly accessible via URL, allowing server-side code execution. At time of publication no known patches exist.

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 · high confidence

The quickUpload() endpoint in Hytale Modding Wiki 1.2.0 and prior validates uploaded files by checking MIME type via PHP's finfo (inspecting file contents) but constructs the stored filename using the client-supplied extension from getClientOriginalExtension(). An attacker can bypass the MIME allowlist by uploading a file with allowed content (e.g., image data) but a .php extension, which gets stored on the public disk and is directly accessible via URL, enabling arbitrary server-side code execution.

MitigationImplement strict extension whitelisting and either rename uploaded files to random identifiers or strip dangerous extensions entirely before storing on disk. Ensure uploaded files are never stored in publicly accessible directories or require server-side script execution to serve them.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS 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
Low
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify Hytale Modding Wiki deployment
    Check for the presence of the Hytale Modding Wiki application files, typically found in the web root directory. Look for files named 'wiki', 'hytale', or related naming patterns in the web server document root.
    Affected if The application is present in the environment
  2. Locate the quickUpload endpoint
    Search the application source code for the quickUpload() function definition. In PHP/Laravel applications, this is typically in a controller file handling file uploads. Look for routes containing 'upload' or 'quickUpload' in the route definition files.
    Affected if The quickUpload() function exists and is routable
  3. Verify getClientOriginalExtension() usage
    Examine the quickUpload() function source code. Look for calls to Laravel's getClientOriginalExtension() method being used to determine the final filename or extension of stored files.
    Affected if getClientOriginalExtension() is used for determining the stored filename extension
  4. Confirm web-accessible storage
    Check the application configuration to determine where uploaded files are stored. Examine the upload destination path in the quickUpload() function and verify if this directory is within the web server's document root or accessible via direct URL.
    Affected if Uploaded files are stored in a directory accessible via direct URL (within web root)
  5. Check for extension allowlist validation
    Review the quickUpload() function for any extension validation logic. Look for arrays or lists that define allowed extensions, and verify whether script extensions like .php, .phtml, .php5 are explicitly blocked regardless of MIME type.
    Affected if No extension allowlist exists, or the allowlist does not block executable extensions like .php

The environment is affected if the Hytale Modding Wiki is deployed, uses getClientOriginalExtension() for stored filenames, and stores uploads in a web-accessible directory without strict extension allowlist validation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement strict extension whitelisting and either rename uploaded files to random identifiers or strip dangerous extensions entirely before storing on disk. Ensure uploaded files are never stored in publicly accessible directories or require server-side script execution to serve them.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-34735 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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