CVE-2025-66550 (GCVE-0-2025-66550)

Vulnerability from cvelistv5 – Published: 2025-12-05 16:56 – Updated: 2025-12-05 18:41
VLAI
Title
Nextcloud Calendar attachments of local files are offered to downloaded
Summary
Nextcloud Calendar is a calendar app for Nextcloud. Prior to 4.7.17 and 5.2.4, when a malicious user creates a calendar event with a crafted attachment that links to a download link of a file on the same Nextcloud server, the file would be downloaded without the user confirming the action. This vulnerability is fixed in 4.7.17 and 5.2.4.
Severity
5.7 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-12-05 18:37 UTC
CWE
  • CWE-241 - Improper Handling of Unexpected Data Type
Assigner
References
Impacted products
Vendor Product Version CPE status
nextcloud security-advisories Affected: >= 5.0.0-rc.1, < 5.2.4
Affected: < 4.7.17
guessed Create a notification for this product.
Show details on NVD website
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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