Vulnerability · Published Dec 5, 2025 · Assigned by GitHub_M
CVE-2025-66512Nextcloud Server vulnerable to XSS in SVG images when opened outside of Nextcloud
Medium 5.4
In plain English
A medium-severity security flaw in security-advisories from nextcloud. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities).
Severity (CVSS 3.1)5.4Medium
Exploit odds (30 days)0.3%top 77.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| nextcloud | security-advisories | >= 32.0.0beta1, < 32.0.3< 31.0.12 |
Weakness: CWE-80 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
References
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qcw2-p26m-9gc5 x_refsource_CONFIRM
- https://github.com/nextcloud/viewer/pull/3023 x_refsource_MISC
- https://github.com/nextcloud/viewer/commit/5044a27d61bc40c0f134298d36af91f865335b63 x_refsource_MISC
- https://hackerone.com/reports/3357808 x_refsource_MISC