CVE-2025-66512

MEDIUM5.4

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

Published Dec 5, 2025

Modified 1 months ago

No fix available

Details

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.

References

WEBhttps://github.com/nextcloud/security-advisories/security/advisories/GHSA-qcw2-p26m-9gc5 WEBhttps://github.com/nextcloud/viewer/commit/5044a27d61bc40c0f134298d36af91f865335b63 WEBhttps://github.com/nextcloud/viewer/pull/3023 WEBhttps://hackerone.com/reports/3357808 ADVISORYhttps://www.cve.org/CVERecord?id=CVE-2025-66512

CVSS Analysis

CVSS v3.1

5.4

Exploitability

Attack Vector

NetworkAV:N

Attack Complexity

LowAC:L

Privileges Required

NonePR:N

User Interaction

RequiredUI:R

Scope

UnchangedS:U

Impact

Confidentiality

NoneC:N

Integrity

LowI:L

Availability

LowA:L

5.4/CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L

Weakness Type (CWE)

Other

CWE-80

Ecosystems

Timeline

PublishedDec 5, 2025

ModifiedDec 5, 2025