CVE-2025-66449: c4illin Convertx

High severity, CVSS 8.8. EPSS: 0.8% chance of exploitation in the next 30 days.

ConvertXis a self-hosted online file converter. In versions prior to 0.16.0, the endpoint `/upload` allows an authenticated user to write arbitrary files on the system, overwriting binaries and allowing code execution. The upload function takes `file.name` directly from user supplied data without doing any sanitization on the name thus allowing for arbitrary file write. This can be used to overwrite system binaries with ones provided from an attacker allowing full code execution. Version 0.16.0 contains a patch for the issue.

Affected products

• c4illin Convertx: before 0.16.0 (fixed in 0.16.0)

Published 2025-12-16. Last modified 2026-10-07.