CVE-2026-33645: Shaneisrael Fireshare

High severity, CVSS 8.1. EPSS: 0.5% chance of exploitation in the next 30 days.

Fireshare facilitates self-hosted media and link sharing. In version 1.5.1, an authenticated path traversal vulnerability in Fireshare’s chunked upload endpoint allows an attacker to write arbitrary files outside the intended upload directory. The `checkSum` multipart field is used directly in filesystem path construction without sanitization or containment checks. This enables unauthorized file writes to attacker-chosen paths writable by the Fireshare process (e.g., container `/tmp`), violating integrity and potentially enabling follow-on attacks depending on deployment. Version 1.5.2 fixes the issue.

Affected products

• Shaneisrael Fireshare: version 1.5.1 only

Published 2026-03-26. Last modified 2026-06-17.