{"id":"GHSA-jmvr-r5hm-fxfr","summary":"Mattermost doesn't enforce request body size limits on plugin HTTP endpoints","details":"Mattermost versions 11.6.x \u003c= 11.6.0, 11.5.x \u003c= 11.5.3, 11.4.x \u003c= 11.4.4, 10.11.x \u003c= 10.11.14 fail to enforce request body size limits on plugin HTTP endpoints which allows an attacker to cause a denial of service via crafted oversized HTTP requests.. Mattermost Advisory ID: MMSA-2026-00646","aliases":["CVE-2026-5308","GO-2026-5836"],"modified":"2026-07-07T16:11:32.128311465Z","published":"2026-05-26T13:30:15Z","database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-06-29T22:41:48Z","nvd_published_at":"2026-05-22T11:16:23Z","cwe_ids":["CWE-400"]},"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-5308"},{"type":"WEB","url":"https://github.com/mattermost/mattermost-plugin-github/commit/9b41b1fd43c408f4be53026ee337bbeaa74ad47c"},{"type":"PACKAGE","url":"https://github.com/mattermost/mattermost"},{"type":"WEB","url":"https://mattermost.com/security-updates"}],"affected":[{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.6.0"},{"fixed":"11.6.1"}]}],"versions":["11.6.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-jmvr-r5hm-fxfr/GHSA-jmvr-r5hm-fxfr.json"}},{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.5.0"},{"fixed":"11.5.4"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-jmvr-r5hm-fxfr/GHSA-jmvr-r5hm-fxfr.json"}},{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.4.0"},{"fixed":"11.4.5"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-jmvr-r5hm-fxfr/GHSA-jmvr-r5hm-fxfr.json"}},{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"10.11.0"},{"fixed":"10.11.15"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-jmvr-r5hm-fxfr/GHSA-jmvr-r5hm-fxfr.json"}},{"package":{"name":"github.com/mattermost/mattermost-plugin-github","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-plugin-github"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.0.1-0.20260410143745-9b41b1fd43c4"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-jmvr-r5hm-fxfr/GHSA-jmvr-r5hm-fxfr.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}