Low 3.3Published Dec 5, 2025

CVE-2025-66546Nextcloud Calendar app allowed booking appointments without the generated token

Updated under an hour ago (Oct 26, 2026, 2:23 PM ET)

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It affects nextcloud security-advisories and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for nextcloud security-advisories

Exploited in the last 30 days

Nextcloud Calendar is a calendar app for Nextcloud. Prior to 4.7.19, 5.5.6, and 6.0.1, the calendar app allowed blindly booking appointments with a squential ID without known the appointment token. This vulnerability is fixed in 4.7.19, 5.5.6, and 6.0.1.

CVSS: 3.3 LOW (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness (CWE): CWE-639
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Dec 5, 2025
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

nextcloud security-advisories nextcloud:security_advisories (from the name)	from 6.0.0-rc.1, < 6.0.1; from 5.0.0-rc.1, < 5.5.6; from 3.0.0-beta1, < 4.7.19	CNA record
nextcloud calendar nextcloud:calendar	from 4.0.0 before 4.7.19; from 5.0.0 before 5.5.6; 6.0.0; 6.0.0; 6.0.0; 6.0.0; 6.0.0; 6.0.0; and 1 more ranges	NVD

References

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-7x2j-2674-fj95	x-refsource-confirm, patch, vendor-advisory
https://github.com/nextcloud/calendar/pull/7537	x-refsource-misc, issue-tracking
https://github.com/nextcloud/calendar/commit/f41650c3681fc4a4130eb883f5c0899c011326b3	x-refsource-misc, patch
https://hackerone.com/reports/3275810	x-refsource-misc, issue-tracking, vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.