CVE-2026-81845 in mcp-sequential-thinking
Summary
by MITRE • 08/28/2026
A vulnerability has been found in arben-adm mcp-sequential-thinking up to 0.5.0. Impacted is the function import_session/export_session of the file mcp_sequential_thinking/server.py of the component Import Session/Export Session. Such manipulation of the argument file_path leads to path traversal. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 0.6.0 is recommended to address this issue. The name of the patch is 2fad3ee8ab1d0868b6c1afb5895bc336a10e5267. Upgrading the affected component is recommended.
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Analysis
by VulDB Data Team • 08/28/2026
The vulnerability identified in arben-adm mcp-sequential-thinking versions up to 0.5.0 represents a critical security flaw within the import_session and export_session functions located in the server.py file of the MCP sequential thinking component. This issue stems from improper validation of user-supplied input, specifically regarding the file_path argument passed during session management operations. The core technical deficiency is a path traversal vulnerability, which allows an attacker to manipulate directory navigation sequences such as dot-dot-slash (../) or backslash variations to escape the intended application directories and access arbitrary files on the underlying host system. This type of flaw typically arises when developers fail to canonicalize file paths before processing them or do not strictly enforce allow-lists for permitted directories, thereby trusting user input without sufficient sanitization checks against directory traversal patterns.
From an operational perspective, this vulnerability poses a severe risk because it can be exploited remotely by unauthenticated attackers who have network access to the service. The ability to traverse file paths means that an attacker could potentially read sensitive configuration files, source code containing hardcoded credentials or API keys, system logs revealing internal architecture details, or other critical data stored on the server's filesystem. In worst-case scenarios where the application runs with elevated privileges, this path traversal could serve as a stepping stone for further exploitation, including remote code execution if combined with other vulnerabilities such as insecure deserialization or file upload flaws that allow writing to executable locations. The fact that an exploit has been publicly disclosed significantly increases the likelihood of automated attacks and widespread compromise across unpatched instances in production environments.
This vulnerability aligns closely with Common Weakness Enumeration (CWE) identifiers, primarily CWE-22: Improper Limitation of a Pathname to a Restricted Directory, which describes how software does not properly restrict pathnames to intended directories. Additionally, it relates to CWE-73: External Control of File Name or Path, as the application accepts external input that directly influences file system operations without adequate safeguards. In terms of offensive security frameworks like MITRE ATT&CK, this flaw facilitates techniques associated with Collection and Exfiltration, specifically allowing adversaries to access local system files for reconnaissance or data theft before moving laterally within a network environment. The remote nature of the attack vector places it in categories related to initial access or privilege escalation depending on the specific outcome achieved by the attacker.
To mitigate this risk immediately, organizations should upgrade arben-adm mcp-sequential-thinking to version 0.6.0 or higher, which incorporates the patch identified as commit hash 2fad3ee8ab1d0868b6c1afb5895bc336a10e5267. This update addresses the root cause by implementing stricter input validation and path canonicalization logic to ensure that all file operations remain confined within the designated application directory structure. Until the upgrade is performed, administrators should consider network-level controls such as restricting access to the affected service endpoints via firewall rules or reverse proxy configurations to limit exposure to trusted IP ranges only. Furthermore, running the application with minimal necessary privileges can help contain potential damage if an exploitation attempt succeeds by preventing the process from reading sensitive system files outside its designated scope. Regular security audits and static code analysis tools should be employed in future development cycles to detect similar path manipulation issues early in the software lifecycle.