CVE-2025-66557 Nextcloud Deck app allowed user with "Can share" permission to modify permissions of other non-owners
Users with share permissions could improperly modify other users' permissions, requiring an upgrade to the Nextcloud Deck app.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-66557?
CVE-2025-66557 is a medium-severity missing authorization vulnerability in nextcloud security-advisories, published on 5 Dec 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-284
Which versions are affected by CVE-2025-66557?
It affects 1 product.
Products include Nextcloud Deck.
How do I fix CVE-2025-66557?
No fix has been published for CVE-2025-66557 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2025-66557 being exploited?
There is no known exploitation of CVE-2025-66557 in the wild and no public exploit code.
Other vulnerabilities in nextcloud security-advisories
- CVE-2021-39225 Missing permission check on Deck API
- CVE-2020-8182 Missing authorization in Nextcloud Deck
- CVE-2021-37631 Circle can be accessed by non-Circle members in Nextcloud Deck
- CVE-2021-22913 Information disclosure in Nextcloud Deck
- CVE-2023-22469 Nextcloud Deck card vulnerable to data leak to unauthorized users via reference preview cache
Sources
Also known as GHSA-wwr8-hx9g-rjvv.