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Fleet CVE-2026-26191

| EUVD-2026-30376 MEDIUM
OS Command Injection (CWE-78)
2026-05-14 https://github.com/fleetdm/fleet GHSA-9vcr-g537-3w5v
6.0
CVSS 4.0
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CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
P
Scope
X

Lifecycle Timeline

5
Patch available
May 14, 2026 - 21:32 EUVD
CVSS changed
May 14, 2026 - 20:22 NVD
6.0 (MEDIUM)
Source Code Evidence Fetched
May 14, 2026 - 14:03 vuln.today
Analysis Generated
May 14, 2026 - 14:03 vuln.today
CVE Published
May 14, 2026 - 13:17 nvd
MEDIUM

DescriptionNVD

Summary

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.

Impact

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.

Workarounds

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.

For more information

If you have any questions or comments about this advisory:

Email us at [[security@fleetdm.com](mailto:security@fleetdm.com)](mailto:security@fleetdm.com)

Join #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw)

Credits

We thank @secfox-ai for responsibly reporting this issue.

AnalysisAI

OS command injection in Fleet's software installer pipeline allows arbitrary code execution as root (macOS/Linux) or SYSTEM (Windows) on managed endpoints when a specially crafted software package is uninstalled. The vulnerability exists because package metadata fields are not sanitized before being incorporated into auto-generated uninstall scripts. …

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CVE-2026-26191 vulnerability details – vuln.today

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