CVE-2025-66512
5.4 · MEDIUMOverview
CVE-2025-66512 is a medium-severity vulnerability affecting nextcloud nextcloud_server. It was published on December 5, 2025 and has a CVSS 3.1 base score of 5.4 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.4, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from nextcloud. Update nextcloud_server to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| nextcloud | nextcloud_server | >= 31.0.0, < 31.0.12 | Affected |
Frequently Asked Questions
What is CVE-2025-66512?
CVE-2025-66512 is a medium-severity vulnerability affecting nextcloud nextcloud_server. It was published on December 5, 2025 and has a CVSS 3.1 base score of 5.4 (MEDIUM).
How severe is CVE-2025-66512?
This vulnerability has a CVSS 3.1 base score of 5.4, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2025-66512?
Check the references section for vendor advisories and patches from nextcloud. Update nextcloud_server to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-66512?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-66512 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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