Medium severity · published Dec 5, 2025
CVE-2025-66557
Nextcloud Deck app allowed user with "Can share" permission to modify permissions of other non-owners
4.3
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 20% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SE
security-advisories · nextcloud
>= 1.15.0-beta.1, < 1.15.2; < 1.14.6 · source: vendor
DE
Deck · Nextcloud
1.14.0 before 1.14.6; 1.15.0 before 1.15.2 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-66557
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-66557
Patch
https://github.com/nextcloud/deck/commit/f1da8b30a455f02373d44154da04494c949a95ae
Issue Tracking
https://github.com/nextcloud/deck/pull/7131
Patch
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-wwr8-hx9g-rjvv
Issue Tracking
https://hackerone.com/reports/3247499
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