CVE-2025-66514
3.5 · LOWOverview
CVE-2025-66514 is a low-severity vulnerability affecting nextcloud mail. It was published on December 5, 2025 and has a CVSS 3.1 base score of 3.5 (LOW).
This vulnerability has a CVSS 3.1 base score of 3.5, rated LOW. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
Nextcloud Mail is the mail app for Nextcloud, a self-hosted productivity platform. Prior to 5.5.3, a stored HTML injection in the Mail app's message list allowed an authenticated user to inject HTML into the email subjects. Javascript was correctly blocked by the content security policy of the Nextcloud Server code.
Remediation
Check the references section for vendor advisories and patches from nextcloud. Update mail 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 | >= 0, < 5.5.3 | Affected |
Frequently Asked Questions
What is CVE-2025-66514?
CVE-2025-66514 is a low-severity vulnerability affecting nextcloud mail. It was published on December 5, 2025 and has a CVSS 3.1 base score of 3.5 (LOW).
How severe is CVE-2025-66514?
This vulnerability has a CVSS 3.1 base score of 3.5, rated LOW. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2025-66514?
Check the references section for vendor advisories and patches from nextcloud. Update mail 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-2025-66514?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-66514 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
AI agents map your attack surface to find vulnerabilities like this one.
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