Summary
A path traversal vulnerability in Langchain-Chatchat allows crafted knowledge base names to escape the configured knowledge base directory. An attacker who can reach the knowledge base creation or document upload interfaces may write content to arbitrary filesystem locations accessible to the application.
A path traversal vulnerability in Langchain-Chatchat allows crafted knowledge base names to escape the configured knowledge base directory. An attacker who can reach the knowledge base creation or document upload interfaces may write content to arbitrary filesystem locations accessible to the application.
Affected context
The vulnerability occurs in the knowledge base creation and document upload interfaces of Langchain-Chatchat versions 0.3.0 and 0.3.1. It becomes risky when the application uses user-controlled knowledge base names in filesystem paths without reliably constraining the resolved path to the configured knowledge base root directory.
The vulnerability occurs in the knowledge base creation and document upload interfaces of Langchain-Chatchat versions 0.3.0 and 0.3.1. It becomes risky when the application uses user-controlled knowledge base names in filesystem paths without reliably constraining the resolved path to the configured knowledge base root directory.
Exploit preconditions
- Attack surface: Knowledge base creation and document upload interfaces
- Required access: Ability to submit requests to an exposed interface; authentication requirements depend on deployment configuration
- Trigger point: Processing of the
knowledge_base_nameparameter when constructing a storage path - Why exploitation is possible: Traversal sequences can cause the resolved destination to fall outside the intended knowledge base root
- Attack surface: Knowledge base creation and document upload interfaces
- Required access: Ability to submit requests to an exposed interface; authentication requirements depend on deployment configuration
- Trigger point: Processing of the
knowledge_base_nameparameter when constructing a storage path - Why exploitation is possible: Traversal sequences can cause the resolved destination to fall outside the intended knowledge base root
Why this happens
The underlying bug is improper neutralization of path traversal elements in a user-controlled path component. When knowledge_base_name is incorporated into filesystem operations without canonicalization and confinement checks, traversal sequences such as ..\ may alter the final resolved path. This behavior maps to CWE-22, Improper Limitation of a Pathname to a Restricted Directory.
The underlying bug is improper neutralization of path traversal elements in a user-controlled path component. When knowledge_base_name is incorporated into filesystem operations without canonicalization and confinement checks, traversal sequences such as ..\ may alter the final resolved path. This behavior maps to CWE-22, Improper Limitation of a Pathname to a Restricted Directory.
Potential impact
- An attacker may write knowledge base or document content outside the intended storage directory.
- Sensitive files could be overwritten or corrupted if the process has sufficient permissions.
- Application integrity could be affected through unauthorized file placement.
- The vulnerability could contribute to code execution or broader host compromise where written files are later trusted or executed.
- An attacker may write knowledge base or document content outside the intended storage directory.
- Sensitive files could be overwritten or corrupted if the process has sufficient permissions.
- Application integrity could be affected through unauthorized file placement.
- The vulnerability could contribute to code execution or broader host compromise where written files are later trusted or executed.
General mitigation guidance
Mitigation generally focuses on treating knowledge base names as identifiers
rather than filesystem paths and enforcing directory confinement.
Common defensive patterns include:
- Allowlisting safe characters and formats for user-controlled names.
- Canonicalizing paths and verifying that the resolved destination remains within the configured root.
- Constructing storage paths with trusted identifiers or managed object storage keys.
- Separating uploaded content from executable and application configuration directories.
- Applying least-privilege filesystem permissions to the service account.
- Using filesystem policies and sandboxing to limit the consequences of unauthorized writes.
- Centralizing path-validation logic so all upload and knowledge base operations use the same controls.
Mitigation generally focuses on treating knowledge base names as identifiers
rather than filesystem paths and enforcing directory confinement.
Common defensive patterns include:
- Allowlisting safe characters and formats for user-controlled names.
- Canonicalizing paths and verifying that the resolved destination remains within the configured root.
- Constructing storage paths with trusted identifiers or managed object storage keys.
- Separating uploaded content from executable and application configuration directories.
- Applying least-privilege filesystem permissions to the service account.
- Using filesystem policies and sandboxing to limit the consequences of unauthorized writes.
- Centralizing path-validation logic so all upload and knowledge base operations use the same controls.
How teams detect issues like this
Organizations can look for path traversal risks through:
- Static analysis rules that flag user input passed into filesystem path construction.
- Code review checks for concatenation or joining of untrusted values without canonicalization and root-boundary validation.
- Runtime monitoring for requests containing traversal markers, encoded separators, or unusual path normalization patterns.
- File-integrity monitoring for writes outside approved knowledge base directories.
- Policy enforcement that restricts service processes from writing to sensitive or executable locations.
- Automated security review tools that identify unsafe path handling patterns during development.
Organizations can look for path traversal risks through:
- Static analysis rules that flag user input passed into filesystem path construction.
- Code review checks for concatenation or joining of untrusted values without canonicalization and root-boundary validation.
- Runtime monitoring for requests containing traversal markers, encoded separators, or unusual path normalization patterns.
- File-integrity monitoring for writes outside approved knowledge base directories.
- Policy enforcement that restricts service processes from writing to sensitive or executable locations.
- Automated security review tools that identify unsafe path handling patterns during development.
Sources
| Source | Link |
|---|---|
| gist. | gist.github.com/ |
| github. | github.com/ |
