{"id":"EUVD-2026-30738","revision":"db7d5829e9674cf5bb18753db9d06a54","records":[{"revision":"db7d5829e9674cf5bb18753db9d06a54","observedAt":"2026-11-07T06:34:20.976+00:00","statement":{"source":"euvd","id":"EUVD-2026-30738","aliases":["CVE-2026-28759","GHSA-8h9w-w78c-vvr3"],"title":"Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate that a remote cluster has access to a channel before processing membership removal requests during shared channel membership sync, which allows a m…","description":"Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate that a remote cluster has access to a channel before processing membership removal requests during shared channel membership sync, which allows a malicious remote cluster to remove any user from any channel, including private channels, via crafted membership sync messages targeting channels the remote cluster is not authorized to access. Mattermost Advisory ID: MMSA-2026-00576","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","score":4.3,"severity":null}],"references":["https://mattermost.com/security-updates"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-30738","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"May 18, 2026, 6:50:07 AM","dateUpdated":"May 18, 2026, 2:36:08 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-30738","identifiers":["EUVD-2026-30738","CVE-2026-28759","GHSA-8h9w-w78c-vvr3"]},"retained":false,"historicalAffected":[]}],"coverage":[]}