What’s Vulnerable › Vulnerabilities

CVE-2026-45225: Heym < 0.0.21 Path Traversal File Upload via upload_file()

• Severity: high (CVSS 7.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-12 · updated 2026-10-26
• Weakness: CWE-22

Description

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

How to fix

Upgrade to a fixed version: heymrun heym 0.0.21. Check the vendor advisory for mitigations.

References

• https://github.com/heymrun/heym/commit/835843e6d2bf7d018cbb8e50f28f0426eaa20c84
• https://github.com/heymrun/heym/pull/92
• https://github.com/heymrun/heym/releases/tag/v0.0.21
• https://www.vulncheck.com/advisories/heym-path-traversal-file-upload-via-upload-file
• https://github.com/heymrun/heym/pull/92

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