SB2025120821 - Use of insufficiently random values in Nextcloud Calendar
Published: December 8, 2025
Security Bulletin ID
SB2025120821
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use of insufficiently random values (CVE-ID: CVE-2025-66511)
CWE-ID: CWE-330 - Use of Insufficiently Random Values
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to compromise the target system.
The vulnerability exists due to the affected application generates participant tokens for meeting proposals using a hash function. A remote attacker can compute valid participant tokens and request details and submit dates in meeting proposals.
Remediation
Install update from vendor's website.