CVE-2026-101045 Fleet Homebrew Cask OS Command Injection via Metadata
Attackers can execute arbitrary commands as root on managed macOS hosts by injecting shell metacharacters into Homebrew cask metadata processed by Fleet.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-101045?
CVE-2026-101045 is a high-severity command injection vulnerability in fleetdm fleet, published on 27 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
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.
Weakness: CWE-78
Which versions are affected by CVE-2026-101045?
How do I fix CVE-2026-101045?
No fix has been published for CVE-2026-101045 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-101045 being exploited?
There is no known exploitation of CVE-2026-101045 in the wild and no public exploit code.
Sources
Also known as GHSA-v4vj-w767-q8qv.