CVE-2026-45225: Heymrun Heym

High severity, CVSS 7.6. EPSS: 0.5% chance of exploitation in the next 30 days.

Heym before 0.0.21 contains a path traversal vulnerability in the file upload endpoint that allows authenticated users to write attacker-controlled files to arbitrary locations by supplying a crafted filename with traversal sequences. Attackers can exploit the unvalidated filename parameter in the upload_file() handler to bypass path restrictions and write, read, or delete files outside the intended storage directory.

Affected products

• Heymrun Heym: before 0.0.21 (fixed in 0.0.21)

Published 2026-05-12. Last modified 2026-07-14.