{"cve":"CVE-2026-3115","nvd":{"published":"2026-03-26T17:16:42.660","modified":"2026-06-17T10:43:04.240","status":"Analyzed","description":"Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","score":4.3},"cwes":["CWE-863"],"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-2026-3115","score":0.0024,"percentile":0.15155,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-mpc7-mm28-f6wq","url":"https://osv.dev/vulnerability/GHSA-mpc7-mm28-f6wq","summary":"Mattermost allows authenticated guest users to enumerate user IDs outside their allowed visibility scope","modified":"2026-06-25T23:11:15.146322253Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","ranges":[">=11.4.0 <11.4.1"],"fixed":["11.4.1"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","ranges":[">=11.3.0-rc1 <11.3.2"],"fixed":["11.3.2"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","ranges":[">=11.2.0-rc1 <11.2.3"],"fixed":["11.2.3"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","ranges":[">=10.11.0-rc1 <10.11.11"],"fixed":["10.11.11"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","ranges":[">=8.0.0-20260105080200-d27a2195068d <8.0.0-20260217110922-b7d4a1f1f59b"],"fixed":["8.0.0-20260217110922-b7d4a1f1f59b"]}]},{"id":"GO-2026-5512","url":"https://osv.dev/vulnerability/GO-2026-5512","summary":"Mattermost allows authenticated guest users to enumerate user IDs outside their allowed visibility scope in github.com/mattermost/mattermost-server","modified":"2026-06-25T23:01:15.836610898Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=10.11.0-rc1+incompatible <10.11.11+incompatible",">=11.2.0-rc1+incompatible <11.2.3+incompatible",">=11.3.0-rc1+incompatible <11.3.2+incompatible",">=11.4.0+incompatible <11.4.1+incompatible"],"fixed":["10.11.11+incompatible","11.2.3+incompatible","11.3.2+incompatible","11.4.1+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":[">=8.0.0-20260105080200-d27a2195068d <8.0.0-20260217110922-b7d4a1f1f59b"],"fixed":["8.0.0-20260217110922-b7d4a1f1f59b"]}]}],"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."]}