{"cve":"CVE-2026-6739","nvd":{"published":"2026-06-12T17:16:27.290","modified":"2026-06-18T14:35:51.673","status":"Analyzed","description":"Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-in role permissions via the role patch API.. Mattermost Advisory ID: MMSA-2026-00656","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","score":7.2},"cwes":["CWE-863"],"references":["https://mattermost.com/security-updates"],"products":["mattermost:mattermost_server"],"source":"nvd","synced_at":"2026-10-19T22:38:48.522727527+00:00"},"epss":{"cve":"CVE-2026-6739","score":0.00257,"percentile":0.17408,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-m2w9-h2mm-79qr","url":"https://osv.dev/vulnerability/GHSA-m2w9-h2mm-79qr","summary":"Mattermost doesn't require system-level permission when patching protected default system roles","modified":"2026-09-10T03:51:08.919891159Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.6.0 <11.6.1"],"fixed":["11.6.1"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.5.0 <11.5.5"],"fixed":["11.5.5"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=10.11.0 <10.11.17"],"fixed":["10.11.17"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","ranges":[">=8.0.0-20250731163400-5b955468ea1e <8.0.0-20260501142004-99b73d4c4acf"],"fixed":["8.0.0-20260501142004-99b73d4c4acf"]}]},{"id":"GO-2026-6285","url":"https://osv.dev/vulnerability/GO-2026-6285","summary":"Mattermost doesn't require system-level permission when patching protected default system roles in github.com/mattermost/mattermost-server","modified":"2026-08-26T01:13:02.633880763Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=10.11.0+incompatible <10.11.17+incompatible",">=11.5.0+incompatible <11.5.5+incompatible",">=11.6.0+incompatible <11.6.1+incompatible"],"fixed":["10.11.17+incompatible","11.5.5+incompatible","11.6.1+incompatible"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server/v5","purl":"pkg:golang/github.com/mattermost/mattermost-server/v5","ranges":["all versions"],"fixed":[]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server/v6","purl":"pkg:golang/github.com/mattermost/mattermost-server/v6","ranges":["all versions"],"fixed":[]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","ranges":[">=8.0.0-20250731163400-5b955468ea1e <8.0.0-20260501142004-99b73d4c4acf"],"fixed":["8.0.0-20260501142004-99b73d4c4acf"]}]}],"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."]}