CVE-2020-8139

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-03-20 · updated 2026-06-17
Weakness: CWE-284

Description

A missing access control check in Nextcloud Server < 18.0.1, < 17.0.4, and < 16.0.9 causes hide-download shares to be downloadable when appending /download to the URL.

Affected products

Fedoraproject Fedora: 32
Nextcloud Server: from 16.0.0 before 16.0.9; from 17.0.0 before 17.0.4; from 18.0.0 before 18.0.1 — fixed in 16.0.9, 17.0.4, 18.0.1

How to fix

Upgrade to a fixed version: Nextcloud Server 16.0.9, 17.0.4, 18.0.1. Check the vendor advisory for mitigations.

References

https://hackerone.com/reports/788257
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KC6HLX5SG4PZO6Y54D2LFJ4ATG76BKOP/
https://nextcloud.com/security/advisory/?id=NC-SA-2020-015
https://hackerone.com/reports/788257
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KC6HLX5SG4PZO6Y54D2LFJ4ATG76BKOP/
https://nextcloud.com/security/advisory/?id=NC-SA-2020-015

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