---
id: CVE-2026-45225
title: Heym < 0.0.21 Path Traversal File Upload via upload_file()
summary: >-
  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.
  At…
severity: high
cvss: 7.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L'
cvssSource: cna
cwe:
  - CWE-22
vendor: heymrun
product: heym
affected:
  - heym < 0.0.21
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-05-14T20:02:11.938210Z'
exploitAvailable: true
published: '2026-05-12'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T14:03:40.252Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-45225'
references:
  - url: 'https://github.com/heymrun/heym/releases/tag/v0.0.21'
    label: heym 0.0.21 Release Notes
  - url: 'https://github.com/heymrun/heym/pull/92'
  - url: >-
      https://github.com/heymrun/heym/commit/835843e6d2bf7d018cbb8e50f28f0426eaa20c84
  - url: >-
      https://www.vulncheck.com/advisories/heym-path-traversal-file-upload-via-upload-file
tags:
  - cve.org
  - exploit-available
epss: 0.00355
epssPercentile: 0.29454
ingestedAt: '2026-11-08T14:51:22.424Z'
---

## Overview

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

- `heym < 0.0.21`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.