Description

Coolify before 4.2.0 fails to properly escape environment variable key names in Docker commands executed over SSH on managed servers. Authenticated attackers can inject shell metacharacters into environment variable keys to execute arbitrary commands on the server host outside containers.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-02T01:17:24.243Z",
  "pubdate": "2026-09-02T01:17:24.243Z",
  "executiveSummary": "Coolify versions prior to 4.2.0 are susceptible to an OS command injection vulnerability arising from insufficient sanitization of environment variable keys.\nThe vulnerability resides in the interaction between the Coolify management interface and managed server hosts via SSH.\nAn authenticated attacker can craft malicious environment variable keys containing shell metacharacters, which are subsequently interpreted and executed by the shell during the container deployment or management process.\nSuccessful exploitation allows for arbitrary code execution on the host system, bypassing container isolation boundaries.\nThe risk is critical as it enables lateral movement, privilege escalation, and full host compromise.\nThe attack requires valid application authentication, but once authenticated, the attacker can execute commands with the privileges of the user account managing the SSH session.",
  "technicalDetails": "The vulnerability stems from improper input validation and sanitization within the Coolify codebase when constructing Docker commands intended for remote execution on managed servers via SSH.\nWhen an administrator or authorized user defines environment variables for a project or service, the application fails to enforce strict character restrictions on the environment variable keys.\nDuring the deployment phase, Coolify serializes these variables and transmits them to the remote server to be injected into the Docker execution context.\nThe remote execution routine improperly handles these keys, failing to escape shell metacharacters (such as backticks, semicolons, dollar signs, or pipes) before passing the string to a command-line interface.\nAn attacker can exploit this by inputting a key name structured as an arbitrary shell command. For example, a key defined as 'MYVAR; touch /tmp/pwned' will be concatenated directly into a Docker CLI command.\nWhen the remote host receives this command, the shell interprets the metacharacters, leading to the execution of the injected command payload.\nThe attack flow follows these steps: 1) The attacker authenticates to the Coolify dashboard; 2) The attacker navigates to the configuration settings for an application or service; 3) The attacker defines a new environment variable where the key field contains a shell-injection payload; 4) The attacker triggers a deployment or configuration update; 5) The server executes the malicious payload via an unescaped system call during the Docker interaction; 6) The command is executed on the underlying host, outside the containerized environment.\nThis vulnerability is particularly dangerous because it grants the attacker execution capabilities on the host infrastructure, effectively breaking the Docker container sandbox. The impact includes full read/write access to host files, persistence mechanisms, and the ability to pivot into internal networks accessible from the host. As the commands are executed through the SSH session established by Coolify, they inherit the security context and permissions of the user associated with that SSH connection."
}