CVE-2026-55441
Received Received - Intake
Command Execution in Mise via Tera Template

Publication date: 2026-06-26

Last updated on: 2026-06-26

Assigner: GitHub, Inc.

Description
mise manages dev tools like node, python, cmake, and terraform. Prior to 2026.6.4, mise's trust feature gates config files (mise.toml, .tool-versions) through trust_check, but task-include files are loaded on a path that never reaches it. When a directory has a task-include dir (mise-tasks/, .mise/tasks/, …) but no config file, mise falls back to the default includes and renders each task's tera fields — and that tera environment has exec() registered. A {{ exec(command='…') }} in any rendered field runs arbitrary commands the moment the tasks are merely listed. There's no config file to gate on, so no trust prompt ever appears. Read-only commands trigger it: mise tasks, mise task ls, mise run, mise tasks --usage (the query shell completion runs on Tab). The victim only has to cd into a cloned repo and list or tab-complete a task. This vulnerability is fixed in 2026.6.4.
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Meta Information
Published
2026-06-26
Last Modified
2026-06-26
Generated
2026-06-26
AI Q&A
2026-06-26
EPSS Evaluated
N/A
NVD
CVE-2026-55441
EUVD
EUVD-2026-39815
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-78 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.
CWE-94 The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
CWE-732 The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
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Executive Summary

CVE-2026-55441 is a high-severity vulnerability in the mise tool (versions prior to 2026.6.4) that allows arbitrary command execution. The issue occurs because mise's trust feature only checks config files like mise.toml or .tool-versions, but task-include files located in directories such as mise-tasks/ or .mise/tasks/ bypass this trust check.

When a directory has a task-include directory but no config file, mise loads default task-includes and renders Tera templates that include an exec() function. This function can execute arbitrary commands embedded in task fields immediately when tasks are listed or tab-completed, without any trust prompt appearing.

An attacker can exploit this by placing a malicious task file in a cloned repository, causing commands to run simply by listing or tab-completing tasks.

Impact Analysis

This vulnerability can have severe impacts including unauthorized execution of arbitrary commands on the victim's system. Because the exec() function runs commands embedded in task files without user consent, an attacker can compromise confidentiality, integrity, and availability of the system.

  • Execution of malicious commands with the privileges of the user running mise.
  • Potential data theft or corruption due to unauthorized command execution.
  • System disruption or denial of service by running harmful commands.
  • Low attack complexity and no required privileges make exploitation easier.
Detection Guidance

This vulnerability can be detected by observing the behavior of the mise tool when listing or tab-completing tasks in repositories that do not have a config file (like mise.toml or .tool-versions) but contain task-include directories (e.g., mise-tasks/ or .mise/tasks/).

Commands such as `mise tasks`, `mise task ls`, `mise run`, or `mise tasks --usage` can trigger the vulnerability by rendering task fields that may execute arbitrary commands if malicious task-include files are present.

To detect exploitation or presence of this vulnerability, you can run these commands in your environment and monitor for unexpected command execution or suspicious activity during task listing or tab completion.

Mitigation Strategies

The immediate mitigation step is to upgrade the mise tool to version 2026.6.4 or later, where this vulnerability is fixed.

Until the upgrade is applied, avoid running mise commands that list or tab-complete tasks in repositories that lack config files but contain task-include directories, as these can trigger arbitrary command execution.

Additionally, review and restrict access to untrusted repositories that may contain malicious task-include files to prevent exploitation.

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