# CVE-2026-34391: Fleet Vulnerable to Windows MDM cross-device command disclosure

> A malicious enrolled device can access MDM commands intended for other devices, exposing sensitive configuration data like WiFi credentials and VPN secrets.

- **Severity:** Medium 6.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Mar 2026
- **Updated:** 27 Mar 2026
- **Also known as:** GHSA-wg7j-pcc3-h4rh

## What is CVE-2026-34391?

CVE-2026-34391 is a medium-severity vulnerability in fleetdm fleet, published on 27 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Fleet is open source device management software. Prior to 4.81.1, a vulnerability in Fleet's Windows MDM command processing allows a malicious enrolled device to access MDM commands intended for other devices, potentially exposing sensitive configuration data such as WiFi credentials, VPN secrets, and certificate payloads across the entire Windows fleet. Version 4.81.1 patches the issue.

Weakness: CWE-488 (Exposure of Data Element to Wrong Session)

## Which versions are affected by CVE-2026-34391?

It affects 1 product.


Products: Fleetdm Fleet.

## How do I fix CVE-2026-34391?

No fix has been published for CVE-2026-34391 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-34391 being exploited?

There is no known exploitation of CVE-2026-34391 in the wild and no public exploit code.

## Other vulnerabilities in fleetdm fleet

- [CVE-2020-26276](https://insights.sbomify.com/CVE-2020-26276/): SAML authentication vulnerability in Fleet (critical 10.0)
- [CVE-2026-103264](https://insights.sbomify.com/CVE-2026-103264/): Fleet before 4.87.0 Authentication Bypass via Device Identifiers (critical 9.3)
- [CVE-2026-23518](https://insights.sbomify.com/CVE-2026-23518/): Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment (critical 9.3)
- [CVE-2026-26062](https://insights.sbomify.com/CVE-2026-26062/): Fleet server may terminate unexpectedly when handling certain gRPC requests (high 8.7)
- [CVE-2026-26061](https://insights.sbomify.com/CVE-2026-26061/): Fleet's unbounded request body read allows remote Denial of Service (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34391 and fix it if it is affected.

What it is: CVE-2026-34391 is a medium-severity vulnerability in fleetdm fleet, published on 27 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-34391 in the wild and no public exploit code.

Affected product: fleetdm fleet. 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-2026-34391/ (Markdown: https://insights.sbomify.com/CVE-2026-34391/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34391
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34391
- OSV: https://osv.dev/vulnerability/CVE-2026-34391

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34391/
Summaries are generated and may contain mistakes; the official description above is the record.