CVE-2025-66512: Nextcloud Server

Medium severity, CVSS 6.1. EPSS: 0.3% chance of exploitation in the next 30 days.

Nextcloud Server is a self hosted personal cloud system. In Nextcloud Server and Server Enterprise prior to 31.0.12 and 32.0.3, a missing sanitization allowed malicious users to circumvent the content security policy when a malicious user manages to trick a user it viewing an uploaded SVG outside of the Nextcloud Servers web page.

Affected products

• Nextcloud Nextcloud Server: from 31.0.0, before 31.0.12 (fixed in 31.0.12); from 32.0.0, before 32.0.3 (fixed in 32.0.3)

Published 2025-12-05. Last modified 2026-06-17.