VULNERABILITY INTELLIGENCE

CVE-2025-66511

CVSS score4.8 MEDIUM

EPSS probability0.29%

CISA KEVNot currently listed

Published2025-12-05

Last modified2026-10-18

CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Description

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.

Weakness classification

security-advisories@github.com: CWE-330

Primary references

security-advisories@github.com — Patch
security-advisories@github.com — Issue Tracking
security-advisories@github.com — Patch, Vendor Advisory
security-advisories@github.com — Permissions Required, Vendor Advisory