{"id":"CVE-2026-26304","aliases":["GHSA-4pmx-622h-x359","GO-2026-4812"],"url":"https://o3.security/vulnerability/CVE-2026-26304","summary":"Permission Bypass in Playbook Run Creation","details":"Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthorized runs via the playbook run API. Mattermost Advisory ID: MMSA-2025-00542","published":"2026-03-16T19:53:21.650Z","modified":"2026-09-18T03:46:21.106522380Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"},"epss":{"score":0.00159,"percentile":0.05353,"asOf":"2026-08-31"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-plugin-playbooks","fixedVersion":"1.41.1-0.20260316224925-705f54a81841"}],"fix":{"url":"https://github.com/mattermost/mattermost-plugin-playbooks/commit/705f54a818410f3612df3865bfde608ed471037e","label":"mattermost/mattermost-plugin-playbooks@705f54a"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26304.json"},{"type":"ADVISORY","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26304"},{"type":"WEB","url":"https://github.com/mattermost/mattermost-plugin-playbooks/commit/705f54a818410f3612df3865bfde608ed471037e"},{"type":"PACKAGE","url":"https://github.com/mattermost/mattermost-plugin-playbooks"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-18T03:46:21.106522380Z"}}