copyparty renders unsanitized filenames as HTML when user uploads empty files

中 6.1CVE-2025-27145 · GHSA-m2jw-cj8v-937r · PYSEC-2026-1278 · 25/02/2025 公開 · 17/06/2026 更新

要点

CVE-2025-27145 は copyparty, copyparty (9001) に影響する深刻度「中」 (CVSS 6.1) の脆弱性です。
今後30日間に悪用される確率（EPSS）：0.47%（全脆弱性の 40.6% より高い）。
対処：1.16.15 以降に更新してください。

パッケージ	影響を受けるバージョン	修正済みバージョン
copyparty PyPI	`< 1.16.15`	`1.16.15`
copyparty 9001	`< 1.16.15`	`1.16.15`

概要

Summary

A DOM-Based XSS was discovered in copyparty, a portable fileserver. The vulnerability is considered low-risk.

Details

By handing someone a maliciously-named file, and then tricking them into dragging the file into copyparty's Web-UI, an attacker could execute arbitrary javascript with the same privileges as that user. For example, this could give unintended read-access to files owned by that user. The bug is triggered by the drag-drop action itself; it is not necessary to actually initiate the upload. The file must be empty (zero bytes).

Note: As a general-purpose webserver, it is intentionally possible to upload HTML-files with arbitrary javascript in <script> tags, which will execute when the file is opened. The difference is that this vulnerability would trigger execution of javascript during the act of uploading, and not when the uploaded file was opened.

Proof of Concept (POC)

Create an empty file named <img src=x onerror="alert(1)">
Drag-and-drop the file into the browser to initiate an upload
The alert(1) is executed

NVD の説明

copyparty, a portable file server, has a DOM-based cross-site scripting vulnerability in versions prior to 1.16.15. The vulnerability is considered low-risk. By handing someone a maliciously-named file, and then tricking them into dragging the file into copyparty's Web-UI, an attacker could execute arbitrary javascript with the same privileges as that user. For example, this could give unintended read-access to files owned by that user. The bug is triggered by the drag-drop action itself; it is not necessary to actually initiate the upload. The file must be empty (zero bytes). Note that, as a general-purpose webserver, it is intentionally possible to upload HTML-files with arbitrary javascript in `<script>` tags, which will execute when the file is opened. The difference is that this vulnerability would trigger execution of javascript during the act of uploading, and not when the uploaded file was opened. Version 1.16.15 contains a fix.