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CVE-2026-45286

Nextcloud: Calendar app leaked user identifiers via attendee suggestion endpoint

Published: Jun 1, 2026Updated: Jul 22, 2026 Sources: CVE List NVDCWE-200
4.3MEDIUM
NVD MITRE
EPSS Score
0.3%
Top 79.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

Description

Nextcloud is an open source content collaboration platform. From versions 5.5.13 to before 5.5.17, and 6.2.0 to before 6.2.3, an authenticated user can enumerate users on the same Nextcloud instance by using the Calendar app's endpoint for suggesting attendees. The sharing restrictions, applied to other endpoints, were not effective here. This issue has been patched in versions 5.5.17 and 6.2.3.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:LI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-200NVD-CWE-noinfo

Affected Products

nextcloud
oss-project·DEaka nextcloud server
calendarSaaSWeb App
Cloud & SaaS / saas-application
security-advisoriesSaaSSaaS Service
Cloud & SaaS / saas-application

Exploitability

Official Patch Available
Workaround Available

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Collection
View detailed technique mapping

References

https://github.com/nextcloud/calendar/issues/7971
github.com
https://github.com/nextcloud/calendar/pull/8197
github.com
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-r697-74m9-gvf2
github.com
and 1 more references View all →

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