{"cve":"CVE-2026-21388","nvd":{"published":"2026-04-09T11:16:20.897","modified":"2026-06-17T10:18:36.900","status":"Analyzed","description":"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","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-770"],"references":["https://mattermost.com/security-updates"],"products":["mattermost:mattermost_server"],"source":"nvd","synced_at":"2026-10-19T22:28:59.047572785+00:00"},"epss":{"cve":"CVE-2026-21388","score":0.00311,"percentile":0.24009,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-x274-8qfc-hrgf","url":"https://osv.dev/vulnerability/GHSA-x274-8qfc-hrgf","summary":"Mattermost MS Teams plugin doesn't limit the request body size on the /lifecycle webhook endpoint ","modified":"2026-06-25T23:11:44.514940687Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-plugin-msteams","purl":"pkg:golang/github.com/mattermost/mattermost-plugin-msteams","ranges":["<1.15.1-0.20260213190728-6fe4d295592e"],"fixed":["1.15.1-0.20260213190728-6fe4d295592e"]}]},{"id":"GO-2026-5734","url":"https://osv.dev/vulnerability/GO-2026-5734","summary":"Mattermost MS Teams plugin doesn't limit the request body size on the /lifecycle webhook endpoint in github.com/mattermost/mattermost-plugin-msteams","modified":"2026-06-25T23:01:40.052056970Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-plugin-msteams","purl":"pkg:golang/github.com/mattermost/mattermost-plugin-msteams","ranges":["<1.15.1-0.20260213190728-6fe4d295592e"],"fixed":["1.15.1-0.20260213190728-6fe4d295592e"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}