CVE-2025-66514

Nextcloud Mail stored HTML injection in subject text

Published Dec 5, 2025 CVSS 3.1 · 3.5 Low EPSS < 1% KEV · Not listed
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

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:nextcloud:mail:*:*:*:*:*:nextcloud:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Nextcloud
Nextcloud mail
Vendors & Products Nextcloud
Nextcloud mail
Type Values Removed Values Added
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.
Title Nextcloud Mail stored HTML injection in subject text
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 3.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Dec 8, 2025, 8:10 PM
Reserved
Dec 3, 2025, 3:28 PM
Status
Analyzed
Published
Dec 5, 2025, 6:15 PM
Modified
Oct 15, 2026, 9:10 PM