{"id":"CVE-2026-21388","aliases":["GO-2026-5734"],"url":"https://o3.security/vulnerability/CVE-2026-21388","summary":"Mattermost MS Teams plugin doesn't limit the request body size on the /lifecycle webhook endpoint ","details":"Mattermost Plugins versions <=2.3.1 fail to limit the request body size on the {{/lifecycle}} webhook endpoint which allows an authenticated attacker to cause memory exhaustion and denial of service via sending an oversized JSON payload. Mattermost Advisory ID: MMSA-2026-00610.","published":"2026-04-09T12:31:11Z","modified":"2026-06-25T23:11:44.514940687Z","cvss":{"score":3.7,"severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-plugin-msteams","fixedVersion":"1.15.1-0.20260213190728-6fe4d295592e"}],"fix":{"url":"https://github.com/mattermost/mattermost-plugin-msteams/commit/6fe4d295592ecc8767d67e69286cbeec01be3210","label":"mattermost/mattermost-plugin-msteams@6fe4d29"},"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-21388"},{"type":"WEB","url":"https://github.com/mattermost/mattermost-plugin-msteams/commit/6fe4d295592ecc8767d67e69286cbeec01be3210"},{"type":"PACKAGE","url":"https://github.com/mattermost/mattermost-plugin-msteams"},{"type":"WEB","url":"https://github.com/mattermost/mattermost-plugin-msteams/releases/tag/v2.3.2"},{"type":"WEB","url":"https://mattermost.com/security-updates"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-06-25T23:11:44.514940687Z"}}