What’s Vulnerable › Vulnerabilities

CVE-2021-32655: Files Drop public link can be added as federated share

• Severity: low (CVSS 3.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-01 · updated 2026-06-17
• Weakness: CWE-241

Description

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.11, 20.0.10, and 21.0.2, an attacker is able to convert a Files Drop link to a federated share. This causes an issue on the UI side of the sharing user. When the sharing user opens the sharing panel and tries to remove the "Create" privileges of this unexpected share, Nextcloud server would silently grant the share read privileges. The vulnerability is patched in versions 19.0.11, 20.0.10 and 21.0.2. No workarounds are known to exist.

Affected products

• Nextcloud Server: before 19.0.11; from 20.0.0 before 20.0.10; from 21.0.0 before 21.0.2 — fixed in 19.0.11, 20.0.10, 21.0.2

How to fix

Upgrade to a fixed version: Nextcloud Server 19.0.11, 20.0.10, 21.0.2. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-grph-cm44-p3jv
• https://hackerone.com/reports/1167929
• https://security.gentoo.org/glsa/202208-17
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-grph-cm44-p3jv
• https://hackerone.com/reports/1167929
• https://security.gentoo.org/glsa/202208-17

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