CVE-2026-51860 in Bisheng
Summary
by MITRE • 10/01/2026
bisheng 2.3.0, 2.4.0, and 2.4.0-beta1 is vulnerable to Directory Traversal in src/backend/bisheng/linsight/domain/task_exec.py.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability identified in Bisheng versions 2.3.0 through 2.4.0-beta1 represents a critical directory traversal flaw located within the task execution module, specifically at the file path src/backend/bisheng/linsight/domain/task_exec.py. This security defect arises from insufficient validation of user-supplied input when processing file paths or resource references during task operations. The application fails to properly sanitize or canonicalize these inputs before using them in filesystem access functions, allowing an attacker to manipulate relative path sequences such as dot-dot-slash (../) to escape the intended directory boundaries. This lack of strict boundary enforcement is a classic implementation error that undermines the integrity of file system isolation mechanisms within the backend service.
From a technical perspective, this flaw aligns directly with Common Weakness Enumeration identifier CWE-22: Improper Limitation of a Pathname to a Restricted Directory. The vulnerability exploits the way the operating system resolves relative paths by interpreting traversal sequences as requests to move up one directory level from the current working directory. By injecting these sequences into parameters handled by task_exec.py, an attacker can redirect file read or write operations to arbitrary locations on the server's filesystem. This capability effectively bypasses any intended sandboxing or chroot-like restrictions that might be in place for specific application modules, granting access to sensitive configuration files, source code, environment variables stored in local files, or other critical system resources outside of the designated application root directory.
The operational impact of this vulnerability is severe and multifaceted depending on the execution context of the Bisheng backend service. If the service runs with elevated privileges, such as under a user account with administrative rights, an attacker could potentially read sensitive data from across the entire file system or overwrite critical system files to establish persistence or cause denial of service. Even if running with restricted permissions, the ability to traverse directories allows for unauthorized access to application-specific secrets, database credentials stored in local configuration files, and internal logic details that should remain hidden. This exposure facilitates further attacks such as server-side request forgery (SSRF) by reading local metadata endpoints or enabling remote code execution through crafted file uploads if combined with other vulnerabilities involving file parsing or template injection.
This vulnerability is also relevant to the MITRE ATT&CK framework, specifically mapping to techniques related to Discovery and Collection. The ability to traverse directories supports reconnaissance activities where an attacker maps out the server's structure to identify valuable targets for subsequent exploitation phases. It falls under the broader category of path traversal attacks which are frequently utilized in conjunction with other web application exploits to escalate privileges or exfiltrate data from compromised environments.
To mitigate this risk, immediate patching is required by upgrading Bisheng to a version later than 2.4.0-beta1 where these input validation controls have been corrected. In the interim, if an upgrade is not immediately feasible, administrators should implement strict input validation at the application layer to reject any path components containing relative traversal sequences before they are processed by the task execution module. Additionally, deploying a web application firewall with rules capable of detecting and blocking directory traversal patterns can provide a temporary defensive layer. It is also advisable to run the Bisheng service under a dedicated user account with minimal file system permissions, ensuring that even if an attacker succeeds in traversing directories, they are restricted from accessing sensitive areas outside their designated working directory. Regular security audits focusing on file handling operations and adherence to secure coding standards will help prevent similar issues in future development cycles.