Fleet Homebrew Cask OS Command Injection via Metadata
Published Sep 27, 2026
8.9
HIGHCVSS 4.0
EPSS 0.75%
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
-
- Version 0StatusaffectedConstraints<2026-08-19
- Version
No data.
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
NoTechnical Impact
TotalDecision
n/aAssessed Sep 28, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
Not enough EPSS history yet for a chart. At least two recorded scores are needed.
Percentile over time
Not enough EPSS history yet for a chart. At least two recorded scores are needed.
References (2)
- https://github.com/fleetdm/fleet/security/advisories/GHSA-fv3p-h7wv-2jgm vendor-advisory
- https://www.vulncheck.com/advisories/fleet-homebrew-cask-os-command-injection-via-metadata third-party-advisory
| Link | Providers | Tags |
|---|---|---|
| https://github.com/fleetdm/fleet/security/advisories/GHSA-fv3p-h7wv-2jgm | vendor-advisory | |
| https://www.vulncheck.com/advisories/fleet-homebrew-cask-os-command-injection-via-metadata | third-party-advisory |
Change history (0)
No recorded changes yet.