{"cve":"CVE-2026-8823","nvd":{"published":"2026-06-22T16:16:42.853","modified":"2026-06-26T16:39:58.273","status":"Analyzed","description":"Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L","score":3.8},"cwes":["CWE-863"],"references":["https://mattermost.com/security-updates"],"products":["mattermost:mattermost_server"],"source":"nvd","synced_at":"2026-10-19T22:39:28.638635428+00:00"},"epss":{"cve":"CVE-2026-8823","score":0.00318,"percentile":0.24761,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-xmfh-3ccg-c9fx","url":"https://osv.dev/vulnerability/GHSA-xmfh-3ccg-c9fx","summary":"Mattermost has an Incorrect Authorization issue","modified":"2026-10-01T20:56:22.201788989Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.7.0 <11.7.1"],"fixed":["11.7.1"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=10.11.0 <10.11.18"],"fixed":["10.11.18"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","ranges":["<8.0.0-20260518160100-9bd77d3fc4d2"],"fixed":["8.0.0-20260518160100-9bd77d3fc4d2"]}]},{"id":"GO-2026-6547","url":"https://osv.dev/vulnerability/GO-2026-6547","summary":"Mattermost has an Incorrect Authorization issue in github.com/mattermost/mattermost-server","modified":"2026-10-01T20:45:12.227552731Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=10.11.0+incompatible <10.11.18+incompatible",">=11.7.0+incompatible <11.7.1+incompatible"],"fixed":["10.11.18+incompatible","11.7.1+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":["<8.0.0-20260518160100-9bd77d3fc4d2"],"fixed":["8.0.0-20260518160100-9bd77d3fc4d2"]}]}],"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."]}