CVE-2025-66512

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.

CVSS v3 5.4 MEDIUM

5.4^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 2.5

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qcw2-p26m-9gc5	Patch Vendor Advisory
https://github.com/nextcloud/viewer/commit/5044a27d61bc40c0f134298d36af91f865335b63	Patch
https://github.com/nextcloud/viewer/pull/3023	Issue Tracking
https://hackerone.com/reports/3357808	Issue Tracking Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:nextcloud:nextcloud_server:::::-:::*
	cpe:2.3:a:nextcloud:nextcloud_server:::::enterprise:::*
	cpe:2.3:a:nextcloud:nextcloud_server:::::-:::*
	cpe:2.3:a:nextcloud:nextcloud_server:::::enterprise:::*

History

18 Oct 2026, 14:10

Type	Values Removed	Values Added
Summary		(es) Nextcloud Server es un sistema de nube personal autohospedado. En Nextcloud Server y Server Enterprise versiones anteriores a 31.0.12 y 32.0.3, una falta de sanitización permitió a usuarios maliciosos eludir la política de seguridad de contenidos cuando un usuario malicioso logra engañar a un usuario haciéndole visualizar un SVG subido fuera de la página web del servidor Nextcloud.

Information

Published : 2025-12-05 17:16

Updated : 2026-10-18 14:10

NVD link : CVE-2025-66512

Mitre link : CVE-2025-66512

CVE.ORG link : CVE-2025-66512

JSON object : View

Products Affected

nextcloud

nextcloud_server

CWE

CWE-80

Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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