CVE-2021-3427 Deluge Web-UI vulnerable to XSS through a crafted torrent file

What is CVE-2021-3427?

CVE-2021-3427 is a medium-severity cross-site scripting vulnerability in Deluge-web, published on 26 Aug 2022. 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

The Deluge Web-UI is vulnerable to XSS through a crafted torrent file. The the data from torrent files is not properly sanitised as it's interpreted directly as HTML. Someone who supplies the user with a malicious torrent file can execute arbitrary Javascript code in the context of the user's browser session.

Weakness: CWE-79

Which versions are affected by CVE-2021-3427?

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

Products include Deluge-Torrent Deluge.

How do I fix CVE-2021-3427?

Upgrade deluge to 2.1.0 or later.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2021-3427 being exploited?

There is no known exploitation of CVE-2021-3427 in the wild and no public exploit code.

Other vulnerabilities in Deluge-web

• CVE-2017-9031 Path traversal in n/a Critical 9.8
• CVE-2019-25585 Deluge 1.3.15 Denial of Service via Webseeds Field Medium 6.9
• CVE-2019-25586 Deluge 1.3.15 Denial of Service via URL Field Medium 6.9

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2021-3427, GHSA-5c8p-qhch-qhx6, PYSEC-2022-256, UBUNTU-CVE-2021-3427, openSUSE-SU-2024:12322-1.