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TI-2026-21182 Aliases CVE-2026-26191GHSA-9vcr-g537-3w5v

Fleet vulnerable to OS command injection in software packages

Priority LOW 28CWE-78Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
Present
Impact type
Code execution
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-78.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00773 55th percentileScored 2026-11-07
Fix Fixed fleet (fleetdm): 4.81.1github.com/fleetdm/fleet/v4 (Go): 4.81.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
fleetdmfleetbefore 4.81.14.81.1Patch availableCNA
—github.com/fleetdm/fleet/v4 (Go)before 4.81.14.81.1Patch availableGHSA-9vcr-g537-3w5v
  • fleet Vendorfleetdm Affected before 4.81.1 Fixed in 4.81.1 Patch available CNA
  • github.com/fleetdm/fleet/v4 (Go) Vendor— Affected before 4.81.1 Fixed in 4.81.1 Patch available GHSA-9vcr-g537-3w5v

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:fleetdm:fleet:*:*:*:*:*:*:*:*before 4.81.0Vulnerablefleetdm
  • cpe:2.3:a:fleetdm:fleet:*:*:*:*:*:*:*:* Versions before 4.81.0 Vulnerable ·fleetdm

Remediation

  • Fix · CNA fleet (fleetdm) Fixed in 4.81.1
  • Fix · GHSA-9vcr-g537-3w5v github.com/fleetdm/fleet/v4 (Go) Fixed in 4.81.1 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-26191
  2. 2026-10-03 Alias added: GHSA-9vcr-g537-3w5v

References

Advisory 2

Other 2

  • TI-2026-65639 Fleet before 4.87.0 Authentication Bypass via Device Identifiers CVSS 4.0CRITICAL 9.3
  • TI-2026-18942 Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment CVSS 4.0CRITICAL 9.3
  • TI-2020-16097 SAML authentication vulnerability in Fleet CVSS 3.1CRITICAL 10.0
  • TI-2026-21066 Fleet server may terminate unexpectedly when handling certain gRPC requests CVSS 4.0HIGH 8.7
  • TI-2026-21065 Fleet's unbounded request body read allows remote Denial of Service CVSS 4.0HIGH 8.7
  • TI-2026-20084 Fleet Windows MDM Azure AD JWT Authentication Bypass CVSS 4.0HIGH 8.2
See all 31 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences