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Fleet Affected by Local Privilege Escalation via Tcl Command Injection in Orbit

High severity GitHub Reviewed Published Apr 8, 2026 in fleetdm/fleet • Updated Apr 8, 2026

Package

gomod github.com/fleetdm/fleet/v4 (Go)

Affected versions

< 4.81.1

Patched versions

4.81.1

Description

Summary

The Orbit agent's FileVault disk encryption key rotation flow on collects a local user's password via a GUI dialog and interpolates it directly into a Tcl/expect script executed via exec.Command("expect", "-c", script). Because the password is inserted into Tcl brace-quoted send {%s}, a password containing } terminates the literal and injects arbitrary Tcl commands. Since Orbit runs as root, this allows a local unprivileged user to escalate to root privileges.

CWE

  • CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
  • CWE-94: Improper Control of Generation of Code ('Code Injection')

Impact

  • Local privilege escalation to root: Any unprivileged local user on a managed endpoint can execute arbitrary commands as root

Credit

This vulnerability was discovered and reported by bugbunny.ai.

References

@lukeheath lukeheath published to fleetdm/fleet Apr 8, 2026
Published to the GitHub Advisory Database Apr 8, 2026
Reviewed Apr 8, 2026
Last updated Apr 8, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(2nd percentile)

Weaknesses

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. Learn more on MITRE.

CVE ID

CVE-2026-27806

GHSA ID

GHSA-rphv-h674-5hp2

Source code

Credits

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