{"id":"CVE-2023-2787","aliases":["EUVD-2023-34243","GHSA-8m2w-p6c5-hh6c"],"status":"published","title":"Collapsed Reply Threads APIs leak message contents from private channels","description":"Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0054,"percentile":0.4574,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-862"],"published":"2023-06-16T08:55:39Z","modified":"2026-10-28T02:30:32Z","products":[{"vendor":"mattermost","product":"mattermost"}],"references":[{"url":"https://mattermost.com/security-updates/","tags":["x_transferred","Vendor Advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-2787","tags":["advisory"]},{"url":"https://mattermost.com/security-updates"},{"url":"https://github.com/advisories/GHSA-8m2w-p6c5-hh6c"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/2xxx/CVE-2023-2787.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2023-2787","title":"Collapsed Reply Threads APIs leak message contents from private channels","description":"Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.\n\n","status":"published","published":"2023-06-16T08:55:39.391Z","modified":"2024-12-06T23:03:17.719Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:35:23.645864Z"}],"euvd":[{"id":"EUVD-2023-34243","description":"Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.\n\n","status":"published","published":"2023-06-16T08:55:39Z","modified":"2024-12-06T23:03:17Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-03T00:04:38.652605Z"}],"ghsa":[{"id":"GHSA-8m2w-p6c5-hh6c","title":"Mattermost fails to check channel membership when accessing message threads, allowing an attacker...","description":"Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.\n\n","status":"published","published":"2023-06-16T09:30:24Z","modified":"2024-04-04T04:54:22Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:56:27.816836Z"}],"nvd":[{"id":"CVE-2023-2787","description":"Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.\n\n","status":"published","published":"2023-06-16T09:15:09.92Z","modified":"2026-06-17T05:53:26.423Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:08:06.335469Z"}],"osv":[{"id":"CVE-2023-2787","title":"Collapsed Reply Threads APIs leak message contents from private channels","description":"Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.\n\n","status":"published","published":"2023-06-16T08:55:39.391Z","modified":"2026-10-28T02:30:32.67992623Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T15:44:31.135751Z"}]}}