Vulnerability Description
Fleet is open source device management software. Prior to version 4.81.0, a vulnerability in Fleet's software installer pipeline could allow a crafted software package to execute arbitrary commands as root (macOS/Linux) or SYSTEM (Windows) on managed endpoints when an uninstall is triggered. When a software package (.pkg, .deb, .rpm, .exe, or .msi) is uploaded to Fleet, metadata is extracted from the package binary and used to generate uninstall scripts. In affected versions, this metadata is not properly sanitized before being included in the generated scripts. A specially crafted package containing malicious values in its metadata fields could result in unintended command execution when the uninstall script runs on managed endpoints. Version 4.81.0 contains a patch. If an immediate upgrade is not possible, administrators should avoid uploading software packages obtained from untrusted or unverified sources. Additionally, administrators can manually inspect and edit auto-generated uninstall scripts before deployment.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Fleetdm | Fleet | < 4.81.0 |
Related Weaknesses (CWE)
References
- https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.1Release Notes
- https://github.com/fleetdm/fleet/security/advisories/GHSA-9vcr-g537-3w5vVendor Advisory
FAQ
What is CVE-2026-26191?
CVE-2026-26191 is a vulnerability with a CVSS score of 9.8 (CRITICAL). Fleet is open source device management software. Prior to version 4.81.0, a vulnerability in Fleet's software installer pipeline could allow a crafted software package to execute arbitrary commands as...
How severe is CVE-2026-26191?
CVE-2026-26191 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-26191?
Check the references section above for vendor advisories and patch information. Affected products include: Fleetdm Fleet.