Nextcloud Calendar Security Feature Issue Vulnerability

🗓️ 10 Dec 2025 00:00:00Reported by China National Vulnerability DatabaseType

Nextcloud Calendar has a security vulnerability in insecure generation of meeting proposal participant tokens that an attacker can exploit to affect token computation.

Reporter	Title	Published	Views	Family All 14
BDU FSTEC	The vulnerability of the Nextcloud Calendar application, a cloud-based software for creating and using Nextcloud data storage, relates to the use of insufficiently random values. This vulnerability allows attackers to compromise the confidentiality and integrity of the protected information.	19 Mar 202600:00	–	bdu_fstec
Circl	CVE-2025-66511	5 Dec 202514:50	–	circl
CNNVD	Nextcloud Calendar 安全特征问题漏洞	5 Dec 202500:00	–	cnnvd
CVE	CVE-2025-66511	5 Dec 202516:42	–	cve
Cvelist	CVE-2025-66511 Nextcloud Calendar app used predictable proposal participant tokens	5 Dec 202516:42	–	cvelist
EUVD	EUVD-2025-201444	5 Dec 202516:42	–	euvd
Nextcloud	Calendar app used predictable proposal participant tokens	5 Dec 202508:08	–	nextcloud
Hacker One	Nextcloud: Predictable proposal participant tokens enable unauthorized access and vote submission	15 Oct 202516:45	–	hackerone
NVD	CVE-2025-66511	5 Dec 202517:16	–	nvd
OSV	CVE-2025-66511 Nextcloud Calendar app used predictable proposal participant tokens	5 Dec 202516:42	–	osv