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Calendar CVE-2025-66511

| EUVDEUVD-2025-201444 MEDIUM
Use of Insufficiently Random Values (CWE-330)
2025-12-05 security-advisories@github.com
4.8
CVSS 3.1 · GitHub Advisory
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Severity by source

GitHub Advisory PRIMARY
4.8 MEDIUM
AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

Lifecycle Timeline

4
EUVD ID Assigned
Mar 15, 2026 - 17:08 euvd
EUVD-2025-201444
Analysis Generated
Mar 15, 2026 - 17:08 vuln.today
Patch released
Mar 15, 2026 - 17:08 nvd
Patch available
CVE Published
Dec 05, 2025 - 17:16 nvd
MEDIUM 4.8

DescriptionGitHub Advisory

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.

Analysis

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.

Technical ContextAI

This vulnerability is classified as Use of Insufficiently Random Values (CWE-330).

RemediationAI

A vendor patch is available. Apply it as soon as possible and verify the fix.

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CVE-2025-66511 vulnerability details – vuln.today

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