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Vulnerabilities

Vulnerability · CVE-2025-66554

Contacts app for Nextcloud easily syncs contacts from various devices with your Nextcloud and allows editing.

Published Dec 5, 2025 · catalog updated Oct 15, 2026 · Contacts app for Nextcloud

Check if you run it

No confirmed exploitation is on record for CVE-2025-66554. EPSS is 0.25%. Act only if a listed version of Contacts app for Nextcloud is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Contacts app for Nextcloud).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.4
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.25%
Remediation
Advisory link
Affected products
cpe nextcloud/contacts

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe nextcloud/contactsversion unspecified

How to fix CVE-2025-66554

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-66554. EPSS is 0.25%. Act only if a listed version of Contacts app for Nextcloud is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.25%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 5, 2025 · NIST NVD

    Detected

    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.

  2. Oct 15, 2026 · NIST NVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2025-66554

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-66554

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-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 c

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.