{"id":"CVE-2026-103858","summary":"MISP Incomplete Thread Authorization Allows Unauthorized Read and Post Access to Discussions","details":"MISP contains an incomplete authorization check in the discussion posting functionality. When a user submits a post to a thread or replies to an existing post, the application only verified whether the target thread was restricted to a single organization (org-only distribution). It did not enforce the full thread access control list, including sharing-group membership and event-level visibility.\n\nAs a result, an authenticated user who is outside the relevant sharing group or who does not have visibility on the associated event could:\n\n- Read the thread title and the content of the quoted post\n\n- Submit a new post into the discussion thread\n\nThis constitutes both an information disclosure (reading restricted thread and post content) and an integrity issue (injecting content into a thread the user is not authorized to participate in).\n\nAffected: \u003c2.5.48","modified":"2026-10-04T02:46:33.079552318Z","published":"2026-10-01T11:31:32.840Z","database_specific":{"cwe_ids":["CWE-285"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/103xxx/CVE-2026-103858.json","cna_assigner":"CIRCL"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/103xxx/CVE-2026-103858.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-103858"},{"type":"FIX","url":"https://github.com/MISP/MISP/commit/79fbd4c75"},{"type":"PACKAGE","url":"https://github.com/MISP/MISP"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/misp/misp","events":[{"introduced":"0"},{"fixed":"79fbd4c75"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"2.5.48"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-103858.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"}]}