CVE-2025-66512: Nextcloud Server vulnerable to XSS in SVG images when opened outside of Nextcloud

Published Dec 5, 2025
·
Updated

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 Software

5 affected components
Nextcloud NextCloud Server<31.0.12, <32.0.3
Nextcloud NextCloud Server>=31.0.0<31.0.12
Nextcloud NextCloud Server>=31.0.0<31.0.12
Nextcloud NextCloud Server>=32.0.0<32.0.3
Nextcloud NextCloud Server>=32.0.0<32.0.3

Event History

Dec 5, 2025
CVE Published
via MITRE·04:22 PM
Data Sourced
via MITRE·04:22 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·05:16 PM
RemedyDescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2025-66512?

CVE-2025-66512 is considered a high severity vulnerability due to its potential to allow unauthorized actions through circumvention of content security policies.

2

How do I fix CVE-2025-66512?

To fix CVE-2025-66512, update your Nextcloud Server to version 31.0.12 or later, or to version 32.0.3 or later.

3

What types of systems are affected by CVE-2025-66512?

CVE-2025-66512 affects Nextcloud Server and Server Enterprise versions prior to 31.0.12 and 32.0.3.

4

What are the potential risks associated with CVE-2025-66512?

The risks associated with CVE-2025-66512 include exposing users to malicious content and compromising the security of user data.

5

Is there any workaround for CVE-2025-66512?

There are no officially recommended workarounds for CVE-2025-66512, so upgrading to a patched version is the best course of action.

Contact

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