What’s Vulnerable › Vulnerabilities

CVE-2021-22877

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-03-03 · updated 2026-06-17
• Weakness: CWE-284

Description

A missing user check in Nextcloud prior to 20.0.6 inadvertently populates a user's own credentials for other users external storage configuration when not already configured yet.

Affected products

• Fedoraproject Fedora: 34
• Nextcloud Server: before 20.0.6 — fixed in 20.0.6

How to fix

Upgrade to a fixed version: Nextcloud Server 20.0.6. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/server/issues/24600
• https://github.com/nextcloud/server/pull/25224
• https://hackerone.com/reports/1061591
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L6BO6P6MP2MOWA6PZRXX32PLWPXN5O4S/
• https://nextcloud.com/security/advisory/?id=NC-SA-2021-004
• https://github.com/nextcloud/server/issues/24600
• https://github.com/nextcloud/server/pull/25224
• https://hackerone.com/reports/1061591
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L6BO6P6MP2MOWA6PZRXX32PLWPXN5O4S/
• https://nextcloud.com/security/advisory/?id=NC-SA-2021-004

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