CVE-2025-665575.4MediumCWE-284

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

nextcloud · security-advisories

Affected: nextcloud security-advisories · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.3%probability of exploitation in the next 30 days

22nd percentile

050100

Higher than 22% of scored CVEs

5.4MediumCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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 products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

nextcloud · security-advisories>= 1.15.0-beta.1, < 1.15.2; < 1.14.6

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Improper Access Control · Access Control
Vendor: nextcloud
Published: December 2025
Band: Unlikely (under 1%), December 2025
Bounty reports: 1 disclosed on HackerOne

Disclosed bug bounty reports about CVE-2025-66557

The reports on HackerOne that name this CVE, with HackerOne's own outcome. Titles and metadata only.

Deck app allowed user with "Can share" permission to modify permissions of other non-ownersNextcloud · 2025 · medium severityValid

CoverageNo articles yet

No CyberSIXT article names CVE-2025-66557 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.