CVE-2026-108600 in open-multi-agent
Summary
by MITRE • 10/10/2026
open-multi-agent (@open-multi-agent/core) 1.5.0 through 1.21.2 contains a link following vulnerability in the file_write tool sandbox that allows attackers to create files outside the workspace root by using dangling symlinks. Attackers can plant a dangling symlink in the workspace and steer the agent via prompt injection to write attacker-influenced content anywhere the agent process can write.
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Analysis
by VulDB Data Team • 10/10/2026
The vulnerability identified within open-multi-agent versions 1.5.0 through 1.21.2 represents a critical file system manipulation flaw rooted in improper handling of symbolic links during sandboxed operations. Specifically, this issue affects the file_write tool, which is designed to restrict agent actions to a designated workspace root directory. The core technical failure lies in the application's inability to properly validate or resolve dangling symlinks before performing write operations. When an attacker plants a dangling symlink within the target workspace, they create a reference point that points to a path outside of the intended sandbox boundaries but does not yet exist on the file system. Because the link is dangling, standard directory traversal checks may fail to recognize it as a threat or incorrectly assume it resides within the allowed scope until the moment of write execution.
The operational impact of this vulnerability allows for arbitrary file creation and modification across the host operating system, provided the agent process has sufficient permissions to access those locations. By leveraging prompt injection techniques, an attacker can manipulate the multi-agent system into executing a command that targets the pre-planted dangling symlink. When the file_write tool attempts to write content to this path, the operating system resolves the symbolic link and creates or overwrites files at the target location specified by the symlink's destination. This effectively bypasses the sandbox isolation mechanism, granting the attacker unauthorized access to sensitive areas of the file system such as configuration directories, home folders, or other application data stores that are not part of the agent's designated workspace.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-22: Improper Limitation of a Pathname to a Restricted Directory, commonly known as path traversal. Furthermore, it relates closely to CWE-59: Improper Link Resolution Before File Access, which describes scenarios where symbolic links are not properly validated prior to use. In the context of the MITRE ATT&CK framework, this behavior corresponds to techniques involving file and directory discovery followed by data staging or exfiltration preparation. The ability to write files outside the sandbox enables subsequent stages of an attack chain, such as planting malicious scripts for execution, modifying system configurations to maintain persistence, or stealing sensitive information stored in accessible directories.
Mitigation strategies must focus on enforcing strict path canonicalization and validation before any file system operations are executed. Developers should ensure that all input paths are resolved to their absolute physical locations using secure API calls that do not follow symbolic links during the resolution phase, thereby preventing redirection attacks. Additionally, implementing a whitelist approach for allowed directories and rejecting any write operation where the final resolved path falls outside the predefined workspace root is essential. It is also critical to sanitize inputs against prompt injection vectors, as this vulnerability relies on social engineering of the agent's decision-making process via malicious prompts. Regular security audits focusing on file I/O operations in sandboxed environments will help identify similar logic flaws before they can be exploited in production systems.