CVE-2025-66512

Nextcloud Server vulnerable to XSS in SVG images when opened outside of Nextcloud

Published: Dec 5, 2025Updated: Dec 9, 2025 Sources: CVE List NVD BDUCWE-80

5.4MEDIUM

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:RUser Interaction

Required

Scope

S:UScope

Unchanged

Impact

C:NConfidentiality

None

I:LIntegrity

Low

A:LAvailability

Low

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Weaknesses

CWE-80 CWE-79

Affected Products

nextcloud

oss-project·DEaka nextcloud server

nextcloud serverSaaSSaaS Service

Cloud & SaaS / saas-application

security-advisoriesSaaSSaaS Service

Cloud & SaaS / saas-application

ООО «Ред Софт»

commercial·RUaka red soft

РЕД ОСOn-premOS

Operating Systems / linux-distro

Nextcloud GmbH

commercial·DEaka nextcloud server, nextcloud enterprise server, nextcloud calendar

NextcloudSaaSSaaS Service

Cloud & SaaS / saas-application

Exploitability

Official Patch Available

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques

Execution

Initial Access

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References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qcw2-p26m-9gc5

github.com

https://github.com/nextcloud/viewer/commit/5044a27d61bc40c0f134298d36af91f865335b63

github.com

https://github.com/nextcloud/viewer/pull/3023

github.com

and 7 more references View all →

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