CVE-2021-41178: Nextcloud Server

Medium severity, CVSS 6.5. EPSS: 1.8% chance of exploitation in the next 30 days.

Nextcloud is an open-source, self-hosted productivity platform. Prior to versions 20.0.13, 21.0.5, and 22.2.0, a file traversal vulnerability makes an attacker able to download arbitrary SVG images from the host system, including user provided files. This could also be leveraged into a XSS/phishing attack, an attacker could upload a malicious SVG file that mimics the Nextcloud login form and send a specially crafted link to victims. The XSS risk here is mitigated due to the fact that Nextcloud employs a strict Content-Security-Policy disallowing execution of arbitrary JavaScript. It is recommended that the Nextcloud Server be upgraded to 20.0.13, 21.0.5 or 22.2.0. There are no known workarounds aside from upgrading.

Affected products

• Nextcloud Server: from 20.0.3, before 20.0.13 (fixed in 20.0.13); from 21.0.1, before 21.0.5 (fixed in 21.0.5); from 22.1.1, before 22.2.0 (fixed in 22.2.0)

Published 2021-10-25. Last modified 2026-06-17.