8.7
HIGH CVSS 4.0
CVE-2026-34735
Hytale Modding Vulnerable to Remote Code Execution via File Upload Bypass in `FileController`
Description

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.

INFO

Published Date :

April 2, 2026, 7:21 p.m.

Last Modified :

April 2, 2026, 7:21 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-34735 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 HIGH [email protected]
Solution
Validate both file content type and extension before storing uploaded files.
  • Ensure file extension matches validated MIME type.
  • Store files in a secure, non-executable location.
  • Implement robust file upload validation.
  • Consult vendor for security updates.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-34735.

URL Resource
https://github.com/HytaleModding/wiki/security/advisories/GHSA-2xqq-6778-h4j9
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-34735 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-34735 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-34735 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-34735 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Apr. 02, 2026

    Action Type Old Value New Value
    Added Description 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.
    Added CVSS V4.0 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
    Added CWE CWE-434
    Added Reference https://github.com/HytaleModding/wiki/security/advisories/GHSA-2xqq-6778-h4j9
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.