What’s Vulnerable › Vulnerabilities

CVE-2021-39225: Missing permission check on Deck API

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-25 · updated 2026-06-17
• Weakness: CWE-639

Description

Nextcloud is an open-source, self-hosted productivity platform. A missing permission check in Nextcloud Deck before 1.2.9, 1.4.5 and 1.5.3 allows another authenticated users to access Deck cards of another user. It is recommended that the Nextcloud Deck App is upgraded to 1.2.9, 1.4.5 or 1.5.3. There are no known workarounds aside from upgrading.

Affected products

• Nextcloud Deck: before 1.2.9; from 1.3.0 before 1.4.5; from 1.5.0 before 1.5.3 — fixed in 1.2.9, 1.4.5, 1.5.3

How to fix

Upgrade to a fixed version: Nextcloud Deck 1.2.9, 1.4.5, 1.5.3. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/deck/pull/3316
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-2x96-38qg-3m72
• https://hackerone.com/reports/1331728
• https://github.com/nextcloud/deck/pull/3316
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-2x96-38qg-3m72
• https://hackerone.com/reports/1331728

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