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

> An unauthenticated attacker can execute arbitrary JavaScript in a victim's browser via malicious multimedia tags in copyparty file server.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 28 Jul 2025
- **Updated:** 28 Jul 2025
- **Also known as:** GHSA-9q4r-x2hj-jmvr, PYSEC-2026-1277

## What is CVE-2025-54423?

CVE-2025-54423 is a medium-severity cross-site scripting vulnerability in 9001 copyparty, published on 28 Jul 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2025-54423?

3 open source packages ship an affected version, including copyparty. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `copyparty` | PyPI | All versions | 1.18.5 |
| `copyparty` | PyPI | All versions | 1.18.5 |
| `copyparty` | PyPI | All versions | 1.18.5 |

Products: 9001 Copyparty.

## How do I fix CVE-2025-54423?

Upgrade copyparty to 1.18.5 or later.

## Is CVE-2025-54423 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-54423 exists.

## Other vulnerabilities in 9001 copyparty

- [CVE-2023-41471](https://insights.sbomify.com/CVE-2023-41471/): Cross-site scripting in n/a (high 7.8)
- [CVE-2025-54796](https://insights.sbomify.com/CVE-2025-54796/): Copyparty is vulnerable to Regex Denial of Service (ReDoS) attacks through "Recent Uploads" page (high 7.5)
- [CVE-2023-37474](https://insights.sbomify.com/CVE-2023-37474/): Path traversal in copyparty (high 7.5)
- [CVE-2025-54589](https://insights.sbomify.com/CVE-2025-54589/): copyparty Reflected XSS via Filter Parameter (medium 6.3)
- [CVE-2023-38501](https://insights.sbomify.com/CVE-2023-38501/): copyparty vulnerable to reflected cross-site scripting via k304 parameter (medium 6.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-54423 and fix it if it is affected.

What it is: CVE-2025-54423 is a medium-severity cross-site scripting vulnerability in 9001 copyparty, published on 28 Jul 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-54423 exists.

Affected packages and fixed versions:
- copyparty (PyPI): affected all versions; fixed in 1.18.5
- copyparty (PyPI): affected all versions; fixed in 1.18.5
- copyparty (PyPI): affected all versions; fixed in 1.18.5

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-54423/ (Markdown: https://insights.sbomify.com/CVE-2025-54423/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-54423
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-54423
- OSV: https://osv.dev/vulnerability/CVE-2025-54423

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-54423/
Summaries are generated and may contain mistakes; the official description above is the record.