What’s Vulnerable › Vulnerabilities

CVE-2021-32688: Application specific tokens can change their own scope

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-07-12 · updated 2026-06-17
• Weakness: CWE-285

Description

Nextcloud Server is a Nextcloud package that handles data storage. Nextcloud Server supports application specific tokens for authentication purposes. These tokens are supposed to be granted to a specific applications (e.g. DAV sync clients), and can also be configured by the user to not have any filesystem access. Due to a lacking permission check, the tokens were able to change their own permissions in versions prior to 19.0.13, 20.0.11, and 21.0.3. Thus fileystem limited tokens were able to grant themselves access to the filesystem. The issue is patched in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds aside from upgrading.

Affected products

• Fedoraproject Fedora: 33, 34
• Nextcloud Server: before 19.0.13; from 20.0.0 before 20.0.11; from 21.0.0 before 21.0.3 — fixed in 19.0.13, 20.0.11, 21.0.3

How to fix

Upgrade to a fixed version: Nextcloud Server 19.0.13, 20.0.11, 21.0.3. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-48m7-7r2r-838r
• https://github.com/nextcloud/server/pull/27000
• https://hackerone.com/reports/1193321
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BVZS26RDME2DYTKET5AECRIZDFUGR2AZ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J63NBVPR2AQCAWRNDOZSGRY5II4WS2CZ/
• https://security.gentoo.org/glsa/202208-17
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-48m7-7r2r-838r
• https://github.com/nextcloud/server/pull/27000
• https://hackerone.com/reports/1193321
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BVZS26RDME2DYTKET5AECRIZDFUGR2AZ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J63NBVPR2AQCAWRNDOZSGRY5II4WS2CZ/
• https://security.gentoo.org/glsa/202208-17

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