{"id":"EUVD-2026-30749","revision":"ac3dad52baa640419aefcb4256b52176","records":[{"revision":"ac3dad52baa640419aefcb4256b52176","observedAt":"2026-11-07T13:29:29.138+00:00","statement":{"source":"euvd","id":"EUVD-2026-30749","aliases":["CVE-2026-6339","GHSA-xvcx-mgpc-5xh3"],"title":"Mattermost versions 11.5.x <= 11.5.1, 11.4.x <= 11.4.3 fail to validate the X-Requested-With header on the burn-on-read reveal endpoint which allows an authenticated channel member to force the reveal of a burn-on-read message without recip…","description":"Mattermost versions 11.5.x <= 11.5.1, 11.4.x <= 11.4.3 fail to validate the X-Requested-With header on the burn-on-read reveal endpoint which allows an authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost Advisory ID: MMSA-2026-00636","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:N/A:L","score":4.3,"severity":null}],"references":["https://mattermost.com/security-updates"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-30749","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"May 18, 2026, 8:05:30 AM","dateUpdated":"May 18, 2026, 12:42:01 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-2026-30749","identifiers":["EUVD-2026-30749","CVE-2026-6339","GHSA-xvcx-mgpc-5xh3"]},"retained":false,"historicalAffected":[]}],"coverage":[]}