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.
https://www.vulncheck.com/advisories/heym-path-traversal-file-upload-via-upload-file
https://github.com/heymrun/heym/releases/tag/v0.0.21
https://github.com/heymrun/heym/pull/92
https://github.com/heymrun/heym/commit/835843e6d2bf7d018cbb8e50f28f0426eaa20c84
Published: 2026-05-12
Updated: 2026-05-13
Base Score: 8
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:C/A:P
Severity: High
Base Score: 7.6
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L
Severity: High
Base Score: 7.2
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00036