CVE-2025-66546

Summary

Nextcloud Calendar is a calendar app for Nextcloud. Prior to 4.7.19, 5.5.6, and 6.0.1, the calendar app allowed blindly booking appointments with a squential ID without known the appointment token. This vulnerability is fixed in 4.7.19, 5.5.6, and 6.0.1.

Affected Software

VendorProductVersion RangeStatus
nextcloudsecurity-advisories>= 6.0.0-rc.1, < 6.0.1affected
nextcloudsecurity-advisories>= 5.0.0-rc.1, < 5.5.6affected
nextcloudsecurity-advisories>= 3.0.0-beta1, < 4.7.19affected

Weaknesses

  • CWE-639: CWE-639: Authorization Bypass Through User-Controlled Key

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References