What’s Vulnerable › Vulnerabilities

CVE-2025-66557: Nextcloud Deck app allowed user with "Can share" permission to modify permissions of other non-owners

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-05 · updated 2026-09-25
• Weakness: CWE-284

Description

Nextcloud Deck is a kanban style organization tool aimed at personal planning and project organization for teams integrated with Nextcloud. Prior to 1.14.6 and 1.15.2, a bug in the permission logic allowed users with "Can share" permission to modify the permissions of other recipients. This vulnerability is fixed in 1.14.6 and 1.15.2.

Affected products

• Nextcloud Deck: from 1.14.0 before 1.14.6; from 1.15.0 before 1.15.2 — fixed in 1.14.6, 1.15.2

How to fix

Upgrade to a fixed version: Nextcloud Deck 1.14.6, 1.15.2. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/deck/commit/f1da8b30a455f02373d44154da04494c949a95ae
• https://github.com/nextcloud/deck/pull/7131
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-wwr8-hx9g-rjvv
• https://hackerone.com/reports/3247499

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