Vulnerability in Contacts App for Nextcloud Allows Malicious CSS Manipulation
CVE-2025-66554

3.5LOW

Key Information:

Vendor

Nextcloud
Status
Security-advisories
Vendor
CVE Published:
5 December 2025

What is CVE-2025-66554?

The Contacts app for Nextcloud, which synchronizes and allows editing of contacts from various devices, is susceptible to a vulnerability that permits a malicious user to inject custom CSS files by altering their organization and title fields. This occurs before the app versions 5.5.4, 6.0.6, and 7.2.5, where the content security policy effectively blocks JavaScript and other potentially harmful options. The issue has been addressed in later versions, enhancing the security posture of the application.

Human OS v1.0:
Ageing Is an Unpatched Zero-Day Vulnerability.

Remediate biological technical debt. Prime Ageing uses 95% high-purity SIRT6 activation to maintain genomic integrity and bolster systemic resilience.

Deploy the Patch

Affected Version(s)

security-advisories >= 7.0.0-alpha.1, < 7.2.5 < 7.0.0-alpha.1, 7.2.5

security-advisories >= 6.0.0-alpha1, < 6.0.6 < 6.0.0-alpha1, 6.0.6

security-advisories < 5.5.4 < 5.5.4

References

https://github.com/nextcloud/security-advisories/security...
x_refsource_CONFIRM
https://github.com/nextcloud/contacts/pull/4619
x_refsource_MISC
https://github.com/nextcloud/contacts/commit/d954d098978d...
x_refsource_MISC

CVSS V3.1

Score:
3.5
Severity:
LOW
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

JSON
.