CVE-2026-86541 in knowns
Summary
by MITRE • 09/08/2026
knowns versions before 0.30.0 contain a path traversal vulnerability in the handleCodeReplace() function that allows attackers to overwrite arbitrary files outside the project root. Attackers can supply absolute paths or relative paths containing directory traversal sequences to write malicious content to sensitive files like shell startup scripts or SSH configuration files.
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Analysis
by VulDB Data Team • 09/08/2026
The identified security flaw resides within the handleCodeReplace() function of software versions prior to 0.30.0, representing a critical path traversal vulnerability that compromises the integrity and confidentiality of the host system. This defect stems from insufficient validation of user-supplied input regarding file paths, allowing an attacker to manipulate the destination directory for code replacement operations. By supplying absolute paths or relative paths containing directory traversal sequences such as dot-dot-slash characters, an adversary can bypass intended access controls that restrict write operations to within the project root directory. This lack of proper sanitization enables the overwriting of arbitrary files located outside the designated application boundary, effectively breaking out of the sandboxed environment expected by the software architecture.
The operational impact of this vulnerability is severe due to the potential for remote code execution and persistent system compromise. Attackers can leverage this flaw to overwrite sensitive configuration files or startup scripts that are executed with elevated privileges during system boot or user login processes. Specific targets include shell initialization files such as .bashrc, .profile, or /etc/profile, as well as SSH daemon configurations like sshd_config or authorized_keys. By injecting malicious content into these files, an attacker can establish persistent backdoors, escalate privileges to root or administrative levels, and exfiltrate sensitive data without requiring direct access to the application's internal logic. This capability transforms a simple file write error into a full system compromise vector, as it allows for the modification of critical infrastructure components that govern user sessions and remote access protocols.
From an industry standards perspective, this vulnerability aligns with CWE-22: Improper Limitation of a Pathname to a Restricted Directory, which describes flaws where software does not properly neutralize path sequences that can resolve to a parent directory or other location outside the intended restricted directory. Furthermore, the exploitation technique maps directly to MITRE ATT&CK tactic T1059 Command and Scripting Interpreter under sub-technique T1059.004 Unix Shell, as attackers often use shell scripts for persistence and execution. The ability to modify SSH configurations also relates to T1078 Valid Accounts if the attacker modifies authorized keys to gain legitimate access without a password, or T1546 Event Triggered Execution if startup scripts are altered to run malicious payloads upon system events.
Mitigation strategies must prioritize immediate patching and robust input validation. The most effective remediation is upgrading to version 0.30.0 or later where this issue has been addressed by the vendor through enhanced path normalization and strict boundary checks within the handleCodeReplace() function. For systems that cannot be immediately patched, administrators should implement file integrity monitoring tools such as AIDE or Tripwire to detect unauthorized modifications to critical system files like shell startup scripts and SSH configurations. Additionally, applying principle of least privilege ensures that even if an attacker succeeds in writing malicious content, they may lack the necessary permissions to execute it or modify high-value targets. Input validation should be enforced at multiple layers, ensuring that all file path inputs are canonicalized and verified against a whitelist of allowed directories before any write operations are permitted by the application logic.