CVE-2026-53542 in Termix
Summary
by MITRE • 08/20/2026
Termix is a web-based server management platform with SSH terminal, tunneling, and file editing capabilities. Prior to 2.3.2, the archive creation endpoint in src/backend/ssh/file-manager.ts passes selected file basenames to tar without an end-of-options marker and without making the operands unambiguously relative. A user with access to an SSH file-manager session can select basenames beginning with GNU tar options such as --checkpoint=1 and --checkpoint-action=exec, causing tar, tar.gz, tar.bz2, or tar.xz creation to interpret those names as options. The resulting checkpoint action executes commands on the managed SSH host with the privileges of the connected SSH account, allowing file disclosure, modification, and service disruption. This issue is fixed in version 2.3.2.
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Analysis
by VulDB Data Team • 08/20/2026
Termix operates as a comprehensive web-based server management platform designed to facilitate remote administration through features such as an integrated SSH terminal, network tunneling, and direct file editing capabilities. The software provides users with the ability to manage files on remote hosts directly from their browser interface, including functionality for creating compressed archives of selected directories or files. This convenience feature relies heavily on invoking system utilities like GNU tar to package data efficiently before transmission back to the client. However, prior to version 2.3.2, a critical security flaw existed within the archive creation endpoint located in the source file src/backend/ssh/file-manager.ts. The vulnerability stems from improper input validation and command construction practices when passing user-selected filenames to the tar executable.
The technical root cause of this vulnerability is an argument injection flaw resulting from the failure to use an end-of-options marker, typically represented by double hyphens (--), before appending file operands to the tar command line. In standard Unix utility conventions, arguments following certain flags are interpreted as options unless explicitly delimited. Furthermore, the implementation did not ensure that the provided file basenames were unambiguously treated as relative path operands rather than potential command-line switches. This oversight allows a malicious actor who has gained access to an SSH file-manager session within Termix to manipulate the archive creation process by selecting files with names that mimic GNU tar options. Specifically, attackers can choose filenames starting with sequences such as --checkpoint=1 or --checkpoint-action=exec.
When these specially crafted basenames are passed to the tar utility without proper sanitization, the utility interprets them not as file paths but as executable instructions. The checkpoint functionality in GNU tar is designed for monitoring long-running archive operations, allowing users to define actions that should be performed at specific intervals during archiving. By injecting --checkpoint-action=exec commands through filename manipulation, an attacker can force tar to execute arbitrary shell commands on the managed SSH host. This execution occurs with the privileges of the connected SSH account associated with the Termix session, effectively granting the attacker a remote code execution vector within the context of that user's permissions.
The operational impact of this vulnerability is severe and multifaceted. An authenticated attacker can achieve file disclosure by instructing tar to read sensitive configuration files or source code during the archive process. They can also perform unauthorized modifications to system files, potentially altering configurations or injecting malicious scripts into existing archives for later execution elsewhere. Additionally, the ability to execute arbitrary commands allows for service disruption through denial-of-service attacks against local processes or network services on the host machine. This represents a significant breach of confidentiality and integrity within the managed environment, as it bypasses standard access controls by leveraging legitimate administrative tools in an unintended manner.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-78, which describes Improper Neutralization of Special Elements used in an OS Command, commonly known as OS Command Injection. It also maps to the MITRE ATT&CK framework under techniques related to command and script interpretation, specifically illustrating how attackers can abuse system utilities for lateral movement or persistence if they achieve initial access through other means. The flaw highlights the critical importance of secure coding practices when interfacing with operating system commands from web applications, particularly regarding input validation and argument separation.
To mitigate this vulnerability, organizations running Termix must upgrade to version 2.3.2 or later immediately. This release includes patches that properly sanitize inputs by ensuring file operands are unambiguously relative and by inserting the necessary end-of-options markers before passing filenames to tar. In environments where upgrading is not immediately feasible, administrators should implement strict input validation on any custom integrations involving archive creation, ensuring that only alphanumeric characters and safe path separators are accepted for file names. Additionally, applying principle of least privilege to SSH accounts used within Termix can limit the blast radius if such an injection were attempted in unpatched versions by restricting access to critical system directories and sensitive files.