Path Traversal in Heymrun Heym

CVE-2026-45225

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.

Vulnerability class: Path Traversal (Directory Traversal)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L.

EPSS exploit prediction

EPSS: 0.005 (40.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 40.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-45225: held from 0.004 to 0.005.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001

Affected products

  • Heymrun Heym — versions 0, 835843e6d2bf7d018cbb8e50f28f0426eaa20c84

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-45225?
CVE-2026-45225 is a high-severity vulnerability in Heymrun Heym, classified under Path Traversal. CVSS score: 7.6/10. Published 2026-05-12.
How severe is CVE-2026-45225?
High severity. CVSS v3 base score is 7.6 out of 10.