{"schema_version":"1.9.0","id":"CVE-2026-2578","published":"2026-03-16T11:58:09.834Z","modified":"2026-08-12T03:51:22.527772038Z","aliases":["GHSA-3rhr-jr63-hwq5","GO-2026-4734"],"related":["SUSE-SU-2026:1135-1","openSUSE-SU-2026:21483-1"],"summary":"Information Disclosure via WebSocket Event When Deleting Unrevealed Burn on Read Posts","details":"Mattermost versions 11.3.x <= 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event.. Mattermost Advisory ID: MMSA-2026-00579","affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mattermost/mattermost","events":[{"introduced":"d27a2195068ddfa3ce17cf470f9739e4edb94b83"},{"fixed":"4082c3dcf285e4d1a386d2ef37f14f39dc5a0094"}],"database_specific":{"cpe":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"11.3.0"},{"fixed":"11.3.1"}],"source":"CPE_RANGE"}}],"versions":["v11.3.1-rc1","v11.3.0-rc4","v11.3.0-rc3","v11.3.0","mattermost-redux@11.3.0","@mattermost/types@11.3.0","@mattermost/client@11.3.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-2578.json"}}],"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/2xxx/CVE-2026-2578.json"},{"type":"ADVISORY","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-2578"}],"database_specific":{"cna_assigner":"Mattermost","cwe_ids":["CWE-201"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/2xxx/CVE-2026-2578.json","unresolved_ranges":[{"extracted_events":[{"introduced":"11.3.0"},{"last_affected":"11.3.0"}],"source":"AFFECTED_FIELD"}]},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"}]}