CVE-2026-105798SimpleChat: Stored XSS via group document filename in inline onclick handler
Updated under an hour ago ()
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It affects microsoft simplechat. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.46%, higher than 39% of scored CVEs.
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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.
- CVSS
- 8.7 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.46% (percentile 39)
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Oct 6, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
microsoft simplechat microsoft:simplechat (from the name) | before 0.261.029 | CNA record |
References
- https://github.com/microsoft/simplechat/security/advisories/GHSA-qwcw-r653-j8c6x-refsource-confirm
- https://github.com/microsoft/simplechat/commit/537a259eb048b8f6d1c94193fa0c9683ab0bace9x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.