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Vulnerabilities

Security fix · CVE-2026-45286

Nextcloud is an open source content collaboration platform.

Published Jun 1, 2026 · catalog updated Jul 22, 2026 · Nextcloud is an open

Check if you run it

No confirmed exploitation is on record for CVE-2026-45286. EPSS is 0.46%. Act only if a listed version of Nextcloud is an open is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Nextcloud is an open).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium4.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.46%
Remediation
Advisory link
Affected products
cpe nextcloud/calendar

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe nextcloud/calendarversion unspecified

How to fix CVE-2026-45286

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-45286. EPSS is 0.46%. Act only if a listed version of Nextcloud is an open is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-200: Exposure of Sensitive Information. EPSS 0.46%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 1, 2026 · NIST NVD

    Detected

    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.

  2. Jul 22, 2026 · NIST NVD

    Updated

    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.

Sources

  • FIRST EPSSExploitation probabilityCVE-2026-45286

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-45286

    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 restri

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.