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Vulnerability record · CVE-2021-32726 · published 12 July 2021

CVE-2021-32726: Nextcloud server improper authentication vulnerability

Nextcloud · Nextcloud Server

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, webauthn tokens were not deleted after a user has been deleted. If a victim reused an earlier used username, the previous user could gain access to their account. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.

9.8 CVSS 3.1 Critical EPSS 1.8% · top 22.7% CWE-708 · CWE-708CWE-287 · Improper authentication
9.8CVSS 3.1 base score, v2 7.5
1.8%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References
17 Jun 2026Last modified by NVD

Description

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, webauthn tokens were not deleted after a user has been deleted. If a victim reused an earlier used username, the previous user could gain access to their account. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-6qr9-c846-j8mg Third Party Advisory
https://github.com/nextcloud/server/pull/27532 Third Party Advisory
https://hackerone.com/reports/1202590 Permissions Required
https://security.gentoo.org/glsa/202208-17 Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-6qr9-c846-j8mg Third Party Advisory
https://github.com/nextcloud/server/pull/27532 Third Party Advisory
https://hackerone.com/reports/1202590 Permissions Required
https://security.gentoo.org/glsa/202208-17 Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-32726), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.