{"id":"CVE-2026-103858","aliases":["EUVD-2026-90770","GHSA-vwhj-wmrx-p88c"],"status":"published","title":"MISP Incomplete Thread Authorization Allows Unauthorized Read and Post Access to Discussions","description":"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","severity":{"version":"4.0","score":5.3,"vector":"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00219,"percentile":0.12507,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-285"],"published":"2026-10-01T11:31:32Z","modified":"2026-10-28T02:30:59Z","products":[{"vendor":"misp","product":"misp"}],"references":[{"url":"https://github.com/MISP/MISP/commit/79fbd4c75","tags":["patch","fix"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-103858","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-vwhj-wmrx-p88c"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/103xxx/CVE-2026-103858.json","tags":["advisory"]},{"url":"https://github.com/MISP/MISP","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-103858","title":"MISP Incomplete Thread Authorization Allows Unauthorized Read and Post Access to Discussions","description":"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","status":"published","published":"2026-10-01T11:31:32.84Z","modified":"2026-10-01T15:00:57.587Z","cvss":[{"version":"4.0","score":5.3,"vector":"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","level":"medium","assessor":"cna"}],"cwes":["CWE-285"],"updated_at":"2026-11-02T13:34:37.420074Z"}],"euvd":[{"id":"EUVD-2026-90770","description":"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","status":"published","published":"2026-10-01T11:31:32Z","modified":"2026-10-01T15:00:57Z","cvss":[{"version":"4.0","score":5.3,"vector":"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","level":"medium"}],"updated_at":"2026-11-02T17:27:45.695512Z"}],"ghsa":[{"id":"GHSA-vwhj-wmrx-p88c","title":"MISP contains an incomplete authorization check in the discussion posting functionality. When a...","description":"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","status":"published","published":"2026-10-01T12:31:20Z","modified":"2026-10-01T12:31:28Z","cvss":[{"version":"4.0","score":5.3,"vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium"}],"cwes":["CWE-285"],"updated_at":"2026-11-02T15:12:40.571849Z"}],"nvd":[{"id":"CVE-2026-103858","description":"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","status":"published","published":"2026-10-01T12:17:16.08Z","modified":"2026-10-01T15:17:29.54Z","cvss":[{"version":"4.0","score":5.3,"vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"}],"cwes":["CWE-285"],"updated_at":"2026-11-02T14:12:53.41762Z"}],"osv":[{"id":"CVE-2026-103858","title":"MISP Incomplete Thread Authorization Allows Unauthorized Read and Post Access to Discussions","description":"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","status":"published","published":"2026-10-01T11:31:32.84Z","modified":"2026-10-28T02:30:59.554478427Z","cvss":[{"version":"4.0","score":5.3,"vector":"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","level":"medium"}],"cwes":["CWE-285"],"updated_at":"2026-11-02T15:44:54.236592Z"}]}}