CVE-2026-45281

HIGH EPSS 20.1%
Published Jun 1, 20264w ago · Modified Jun 17, 20261w ago
8.1 CVSS 3.1
High
Find Similar
Published Jun 1, 2026 4w ago
Last Modified Jun 17, 2026 1w ago

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

CVSS Details

Base Score
8.1
Exploitability
2.8
Impact
5.2
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability None

Threat Intelligence

EPSS Exploit Probability
20.1% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-639

Affected Products 15

VendorProductVersionRange
nextcloudnextcloud_server*≥32.0.0  –  <32.0.9
nextcloudnextcloud_server*≥33.0.0  –  <33.0.3
nextcloudnextcloud_server*≥21.0.0  –  <21.0.9.23
nextcloudnextcloud_server*≥22.0.0  –  <22.2.10.39
nextcloudnextcloud_server*≥23.0.0  –  <23.0.12.35
nextcloudnextcloud_server*≥24.0.0  –  <24.0.12.34
nextcloudnextcloud_server*≥25.0.0  –  <25.0.13.29
nextcloudnextcloud_server*≥26.0.0  –  <26.0.13.26
nextcloudnextcloud_server*≥27.0.0  –  <27.1.11.26
nextcloudnextcloud_server*≥28.0.0  –  <28.0.14.17
nextcloudnextcloud_server*≥29.0.0  –  <29.0.16.16
nextcloudnextcloud_server*≥30.0.0  –  <30.0.17.9
nextcloudnextcloud_server*≥31.0.0  –  <31.0.14.5
nextcloudnextcloud_server*≥32.0.0  –  <32.0.9
nextcloudnextcloud_server*≥33.0.0  –  <33.0.3

References 3

  • github.com https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hrrv-mp25-26vv
    MitigationVendor Advisory
  • github.com https://github.com/nextcloud/server/pull/59962
    Issue TrackingPatch
  • hackerone.com https://hackerone.com/reports/3545964
    Permissions Required

Remediation

  • github.com https://github.com/nextcloud/server/pull/59962
    Issue TrackingPatch