Medium 5.4Published Dec 5, 2025

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

Updated under an hour ago (Oct 27, 2026, 10:30 AM ET)

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It affects nextcloud security-advisories and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for nextcloud security-advisories

Exploited in the last 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.

CVSS: 5.4 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Weakness (CWE): CWE-80
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Dec 5, 2025
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

nextcloud security-advisories nextcloud:security_advisories (from the name)	from 32.0.0beta1, < 32.0.3; before 31.0.12	CNA record
nextcloud nextcloud_server nextcloud:nextcloud_server	from 31.0.0 before 31.0.12; from 31.0.0 before 31.0.12; from 32.0.0 before 32.0.3; from 32.0.0 before 32.0.3	NVD

References

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qcw2-p26m-9gc5	x-refsource-confirm, patch, vendor-advisory
https://github.com/nextcloud/viewer/pull/3023	x-refsource-misc, issue-tracking
https://github.com/nextcloud/viewer/commit/5044a27d61bc40c0f134298d36af91f865335b63	x-refsource-misc, patch
https://hackerone.com/reports/3357808	x-refsource-misc, issue-tracking, vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.