CVE-2025-66554

| EUVD-2025-201461 LOW
2025-12-05 [email protected]
3.5
CVSS 3.1

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

Lifecycle Timeline

5
Analysis Generated
Mar 15, 2026 - 17:08 vuln.today
EUVD ID Assigned
Mar 15, 2026 - 17:08 euvd
EUVD-2025-201461
Patch Released
Mar 15, 2026 - 17:08 nvd
Patch available
PoC Detected
Dec 09, 2025 - 17:01 vuln.today
Public exploit code
CVE Published
Dec 05, 2025 - 18:15 nvd
LOW 3.5

Description

Contacts app for Nextcloud easily syncs contacts from various devices with your Nextcloud and allows editing. Prior to 5.5.4, 6.0.6, and 7.2.5, a malicious user was able to modify their organisation and title field to load additional CSS files. Javascript and other options were correctly blocked by the content security policy of the Nextcloud Server code. This vulnerability is fixed in 5.5.4, 6.0.6, and 7.2.5.

Analysis

Contacts app for Nextcloud easily syncs contacts from various devices with your Nextcloud and allows editing. Prior to 5.5.4, 6.0.6, and 7.2.5, a malicious user was able to modify their organisation and title field to load additional CSS files. Javascript and other options were correctly blocked by the content security policy of the Nextcloud Server code. This vulnerability is fixed in 5.5.4, 6.0.6, and 7.2.5.

Technical Context

Cross-site scripting (XSS) allows injection of client-side scripts into web pages viewed by other users due to insufficient output encoding.

Affected Products

Affected products: Nextcloud Contacts

Remediation

A vendor patch is available — apply it immediately. Encode all user-supplied output contextually (HTML, JS, URL). Implement Content Security Policy (CSP) headers. Use HTTPOnly and Secure cookie flags.

Priority Score

38
Low Medium High Critical
KEV: 0
EPSS: +0.0
CVSS: +18
POC: +20

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CVE-2025-66554 vulnerability details – vuln.today

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