CVE-2025-66511
Dec. 10, 2025, 4:14 p.m.
4.8
Medium
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.
Product(s) Impacted
| Vendor | Product | Versions |
|---|---|---|
| Nextcloud |
|
|
Weaknesses
Common security weaknesses mapped to this vulnerability.
CWE-330
Use of Insufficiently Random Values
The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.
*CPE(s)
Affected systems and software identified for this CVE.
| Type | Vendor | Product | Version | Update | Edition | Language | Software Edition | Target Software | Target Hardware | Other Information |
|---|---|---|---|---|---|---|---|---|---|---|
| a | nextcloud | calendar | / | / | / | / | / | / | / | / |
Tags
CVSS Score
CVSS Data - 3.1
- Attack Vector: NETWORK
- Attack Complexity: HIGH
- Privileges Required: NONE
- Scope: UNCHANGED
- Confidentiality Impact: LOW
- Integrity Impact: LOW
- Availability Impact: NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Timeline
Published: Dec. 5, 2025, 5:16 p.m.
Last Modified: Dec. 10, 2025, 4:14 p.m.
Last Modified: Dec. 10, 2025, 4:14 p.m.
Status : Analyzed
CVE has had analysis completed and all data associations made.
More infoSource
security-advisories@github.com
*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.