---
title: "CVE-2026-105798: SimpleChat - Stored XSS"
description: "SimpleChat < 0.261.029 contains a stored XSS caused by improper escaping of attacker-controlled group document filenames in group_workspaces.html, letting authenticated group Owner, Admin, or DocumentManager execute scripts in victim sessions when Share is clicked."
url: https://panop.io/threat-heartbeat/CVE-2026-105798/
---

# CVE-2026-105798 SimpleChat - Stored XSS

SimpleChat < 0.261.029 contains a stored XSS caused by improper escaping of attacker-controlled group document filenames in group\_workspaces.html, letting authenticated group Owner, Admin, or DocumentManager execute scripts in victim sessions when Share is clicked.

CVSS base score 8.7 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.46% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-105798)

## Details

Type

Stored XSS

Impact

Stored XSS, Information Disclosure

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Published

6 October 2026

Updated

15 October 2026

Weakness

[CWE-79](https://cwe.mitre.org/data/definitions/79.html)

## Vendor fix

Update to version 0.261.029 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-105798](https://nvd.nist.gov/vuln/detail/CVE-2026-105798)
- [https://github.com/microsoft/simplechat/security/advisories/GHSA-qwcw-r653-j8c6](https://github.com/microsoft/simplechat/security/advisories/GHSA-qwcw-r653-j8c6)
- [https://github.com/microsoft/simplechat/commit/537a259eb048b8f6d1c94193fa0c9683ab0bace9](https://github.com/microsoft/simplechat/commit/537a259eb048b8f6d1c94193fa0c9683ab0bace9)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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