CVE-2025-66551: Nextcloud Tables is missing an ownership check which allows moving columns into tables of other users

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-639

Description

Nextcloud Tables allows you to create your own tables with individual columns. Prior to 0.8.6 and 0.9.3, a malicious user was able to create their own table and then move a column to a victims table. This vulnerability is fixed in 0.8.6 and 0.9.3.

Affected products

nextcloud Tables: from 0.4.0 before 0.8.6; from 0.9.0 before 0.9.3 — fixed in 0.8.6, 0.9.3

How to fix

Upgrade to a fixed version: nextcloud Tables 0.8.6, 0.9.3. Check the vendor advisory for mitigations.

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-w787-vwqp-8wr7
https://github.com/nextcloud/tables/commit/39f24a62fb41fd7a8bda65325f8bbafdc91c731c
https://github.com/nextcloud/tables/pull/1810
https://hackerone.com/reports/3137895

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