{"id":"CVE-2026-105798","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-105798","generatedAt":"2026-10-28T01:12:19.954Z","title":"Prior to 0.261.029, POST /api/group_documents/upload stores an attacker-controlled group document filename that group_workspaces.html later interpolates into inline Share event handlers.","description":"SimpleChat is a secure AI conversation application with personal and group workspaces for document-grounded interactions. Prior to 0.261.029, POST /api/group_documents/upload stores an attacker-controlled group document filename that group_workspaces.html later interpolates into inline Share event handlers. The escapeGroupHtml function leaves apostrophes unchanged, while escapeHtml produces an HTML entity that the browser decodes before JavaScript evaluation, so either path permits the filename to terminate the handler string. An authenticated group Owner, Admin, or DocumentManager can persist script that executes in the SimpleChat origin when another group member clicks Share, allowing access to victim-visible data and actions with the victim session. This issue is fixed in version 0.261.029.","published":"2026-10-06T15:17:17.000Z","lastModified":"2026-10-06T15:25:01.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":8.7,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N"},"cwe":["CWE-79"],"affected":[],"epss":{"score":0.00465,"percentile":0.40025,"date":"2026-10-26","history":[{"date":"2026-10-07","score":0.00465,"percentile":0.38263}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.46%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-06T15:17:17.000Z","detail":{"score":"8.7","severity":"HIGH","publishedAt":"2026-10-06T15:17:16.880Z"},"summary":"New CVE, high severity (CVSS 8.7)."}],"references":[{"url":"https://github.com/microsoft/simplechat/commit/537a259eb048b8f6d1c94193fa0c9683ab0bace9","source":"security-advisories@github.com"},{"url":"https://github.com/microsoft/simplechat/security/advisories/GHSA-qwcw-r653-j8c6","source":"security-advisories@github.com"},{"url":"https://github.com/microsoft/simplechat/security/advisories/GHSA-qwcw-r653-j8c6","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-105798","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}