CVE-2025-66554

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.

Score

CVSS 3.1 5.4 Medium

Status

Analyzed - security-advisories@github.com

Published

2025-12-05

Last modified

2026-10-15

Weaknesses

CWE-79

Affected products

• Contacts (Nextcloud)
• Security-advisories (Nextcloud)

References

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-9v78-cpfc-v6h2
• https://github.com/nextcloud/contacts/pull/4619
• https://github.com/nextcloud/contacts/commit/d954d098978dde1f121600e8b994e02f293c68b1
• https://hackerone.com/reports/3293290