CVE-2025-66546

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.

• CWE-639

• https://github.com/nextcloud/calendar/commit/f41650c3681fc4a4130eb883f5c0899c011326b3Patch
• https://github.com/nextcloud/calendar/pull/7537Issue Tracking
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-7x2j-2674-fj95Patch, Vendor Advisory
• https://hackerone.com/reports/3275810Issue Tracking, Vendor Advisory

Published

Dec 5, 2025

Last Modified

Jun 17, 2026

Status

Analyzed

• Uncovering a hidden BOLA in Appsmith's snapshot logicStrix autonomously discovered a BOLA/IDOR vulnerability in Appsmith's snapshot deletion path.
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• CVE-2025-66540Rejected reason: Not used
• CVE-2025-66541Rejected reason: Not used
• CVE-2025-66542Rejected reason: Not used
• CVE-2025-66543Rejected reason: Not used
• CVE-2025-66544Rejected reason: Not used
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