Vulnerability · Published Sep 27, 2026 · Assigned by VulnCheck
CVE-2026-101045Fleet Homebrew Cask OS Command Injection via Metadata
High 8.0
In plain English
A high-severity OS command injection in fleet from fleetdm. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 55% of all known vulnerabilities).
Official description
Fleet-maintained app install and uninstall scripts for macOS are generated from Homebrew cask metadata. In manifests generated before 2026-08-19, the script generator escaped this metadata at some interpolation sites but not all of them, so cask metadata containing shell metacharacters (for example $(...) command substitution) could be carried into scripts that execute as root on managed macOS hosts. An attacker who could land crafted metadata in an upstream Homebrew cask — without needing any Fleet credentials — could achieve arbitrary command execution as root on managed macOS hosts that install or uninstall the affected Fleet-maintained app; exploitation required the crafted metadata to pass both upstream Homebrew cask review and Fleet's review of the automated ingestion pull request. The fix (fleetdm/fleet#51324) landed in Fleet's ingestion pipeline on 2026-08-19 so that all manifests generated on or after that date escape cask metadata at every interpolation site; because manifests are generated centrally and distributed as pre-built content, remediation applied to all deployments with no customer action, and the code fix is included in Fleet v4.92.0.
Affected products (as reported)
Weakness: CWE-78 · Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
References
- GitHub Security Advisory (GHSA-fv3p-h7wv-2jgm) vendor-advisory
- VulnCheck Advisory: Fleet Homebrew Cask OS Command Injection via Metadata third-party-advisory