CVE-2026-45281

8.1 HIGH
Published: June 01, 2026 Modified: June 03, 2026
View on NVD

Description

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, with the knowledge of other users’ principal URL an attacker could possibly send a request to gain full access to their calendar. Therefore, the attacker must be an authenticated user. This is because of improper authorization controls in the backend of the calendar. If the attacker had access to the calendar, they would be able to view and modify it. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended that the Nextcloud Enterprise Server is upgraded to 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9, 29.0.16.16, 28.0.14.17, 27.1.11.26, 26.0.13.26, 25.0.13.29, 24.0.12.34, 23.0.12.35, 22.2.10.39, or 21.0.9.23

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hrrv-mp25-26vv
Source: security-advisories@github.com
Mitigation Vendor Advisory
https://github.com/nextcloud/server/pull/59962
Source: security-advisories@github.com
Issue Tracking Patch
https://hackerone.com/reports/3545964
Source: security-advisories@github.com
Permissions Required

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
8.1 / 10.0
EPSS (Exploit Probability)
0.3%
19th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

nextcloud