CVE-2025-66511: Nextcloud Calendar is a calendar app for Nextcloud. Prior to 6.0.3, the Calendar app generates participant tokens for meeting proposals using a hash function…

PriorityP434medium6.5CVSS 3.1

AVNACLPRNUINSUCLILAN

EPSS

0.25%

15.7th percentile

Nextcloud Calendar is a calendar app for Nextcloud. Prior to 6.0.3, the Calendar app generates participant tokens for meeting proposals using a hash function, allowing an attacker to compute valid participant tokens, which allowed them to request details and submit dates in meeting proposals. The tokens are not purely random generated. This vulnerability is fixed in 6.0.3.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
nextcloud	calendar	>= 6.0.0 < 6.0.3	6.0.3
nextcloud	security-advisories	—	—

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