# CVE-2026-105797: Command injection in simplechat

> Authenticated low-privileged users can execute arbitrary OS commands via MCP stdio transport due to an authorization ordering flaw in SimpleChat.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Oct 2026
- **Updated:** 6 Oct 2026
- **Also known as:** GHSA-h4mw-qw8m-5x4j

## What is CVE-2026-105797?

CVE-2026-105797 is a high-severity command injection vulnerability in microsoft simplechat, published on 6 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

SimpleChat is a secure AI conversation application with personal and group workspaces for document-grounded interactions. In versions 0.261.003 and 0.261.027, an authorization ordering flaw in POST /api/user/plugins allows an authenticated low-privileged user to omit the top-level MCP type so that _reject_non_admin_mcp_stdio skips inspection before the type is restored from metadata. The stored personal action can then reach McpPluginFactory.create_connector, and MCPStdioPlugin.connect starts the attacker-selected operating-system process under the application service identity when the action tool is invoked. Exploitation requires personal plugins to be enabled and governance to permit MCP actions, and it can expose or modify secrets and data available to the service or disrupt the service. This issue is fixed in version 0.261.031.

Weakness: CWE-863 (Incorrect Authorization), CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2026-105797?


## How do I fix CVE-2026-105797?

No fix has been published for CVE-2026-105797 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-105797 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105797 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-105797 and fix it if it is affected.

What it is: CVE-2026-105797 is a high-severity command injection vulnerability in microsoft simplechat, published on 6 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105797 exists.

Affected product: microsoft simplechat. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-105797/ (Markdown: https://insights.sbomify.com/CVE-2026-105797/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-105797
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-105797
- OSV: https://osv.dev/vulnerability/CVE-2026-105797

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-105797/
Summaries are generated and may contain mistakes; the official description above is the record.