{"cve":"CVE-2026-26233","nvd":{"published":"2026-03-25T17:16:53.143","modified":"2026-06-17T10:25:59.117","status":"Analyzed","description":"Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to rate limit login requests which allows unauthenticated remote attackers to cause denial of service (server crash and restart) via HTTP/2 single packet attack with 100+ parallel login requests.. Mattermost Advisory ID: MMSA-2025-00566","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-400"],"references":["https://mattermost.com/security-updates"],"products":["mattermost:mattermost_server"],"source":"nvd","synced_at":"2026-10-19T22:28:18.033120106+00:00"},"epss":{"cve":"CVE-2026-26233","score":0.00311,"percentile":0.23943,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-247x-7qw8-fp98","url":"https://osv.dev/vulnerability/GHSA-247x-7qw8-fp98","summary":"Mattermost doesn't rate limit login requests, allowing DoS","modified":"2026-04-06T17:56:39.732177Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.4.0-rc1 <11.4.1"],"fixed":["11.4.1"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.3.0-rc1 <11.3.2"],"fixed":["11.3.2"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.2.0-rc1 <11.2.4"],"fixed":["11.2.4"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=10.11.0-rc1 <10.11.12"],"fixed":["10.11.12"]}]},{"id":"GO-2026-4916","url":"https://osv.dev/vulnerability/GO-2026-4916","summary":"Mattermost doesn't rate limit login requests, allowing DoS in github.com/mattermost/mattermost-server","modified":"2026-04-02T21:20:02.374344Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=10.11.0-rc1+incompatible <10.11.12+incompatible",">=11.2.0-rc1+incompatible <11.2.4+incompatible",">=11.3.0-rc1+incompatible <11.3.2+incompatible",">=11.4.0-rc1+incompatible <11.4.1+incompatible"],"fixed":["10.11.12+incompatible","11.2.4+incompatible","11.3.2+incompatible","11.4.1+incompatible"]}]}],"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."]}