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Secure view shares can be downloaded by manipulating the URL (NC-SA-2020-015)

7th February 2020

Risk level: Low

CVSS v3 Base Score: 0 (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:N)

CWE: Improper Access Control - Generic (CWE-284)

HackerOne report: 788257


A missing access control check in Nextcloud Server 18.0.0 causes hide-download shares to be downloadable when appending /download to the URL.

Affected Software

  • Nextcloud Server < 18.0.1 (CVE-2020-8139)
  • Nextcloud Server < 17.0.4 (CVE-2020-8139)
  • Nextcloud Server < 16.0.9 (CVE-2020-8139)

Action Taken

The error has been fixed.


It is recommended that the Nextcloud Server is upgraded to 18.0.1.


The Nextcloud team thanks the following people for their research and responsible disclosure of the above advisory:

  • NA - Vulnerability discovery and disclosure.

This advisory is licensed CC BY-SA 4.0.

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