CVE-2026-55443
MediumCVSS 5.1Exploitation Probability (EPSS)
Low risk5th percentile — higher than 5% of all known CVEs
Summary
LangChain prior to version 1.3.9 contains a vulnerability where several components that resolve filesystem paths or expand search patterns do not consistently confine the resolved path to the intended root directory. Affected behaviors include file-search middleware, configuration loaders, and path-prefix authorization checks that can allow access to files outside the configured root via glob patterns, symlinks, or path segment boundary bypass.
Risk Assessment
The risk involves potential disclosure of sensitive files outside the intended boundary when LangChain components receive path values, search patterns, or workspace contents from an untrusted source, including an LLM acting on untrusted input.
Recommendation
Immediately update LangChain to version 1.3.9 or later, which contains the fix for this vulnerability.
Original NVD description (English source)
LangChain is a framework for building agents and LLM-powered applications. Prior to 1.3.9, several LangChain components that resolve filesystem paths or expand search patterns do not consistently confine the resolved path to the intended root directory. Affected behaviors include: a file-search agent middleware that validates a starting directory but not the search pattern or the resolved target of matched files, so glob patterns and symlinks can reach files outside the configured root; prompt- and chain/agent-configuration loaders that accept path fields and resolve them without confining the result to a trusted base or rejecting symlink targets; and path-prefix authorization checks that compare by string prefix without a path-segment boundary, so a sibling path sharing the prefix is accepted. When these components receive path values, search patterns, or workspace contents influenced by an untrusted source — including an LLM acting on untrusted input — the result can be disclosure of files outside the intended boundary. This vulnerability is fixed in 1.3.9.