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.

CVSS 3.1

5.4CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS

0.2% chance of exploitation in the next 30 days; higher than 16% of CVEs (scores of 2026-10-25)

CWE

CWE-79

Published

2025-12-05

Modified

2026-10-15

Record from

the NVD, synced 2026-10-19

Affected

• nextcloud:contacts

References

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

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