LangChain: Path traversal and sandbox escape in LangChain file-search middleware and loaders

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.1 · CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

• CVE-2026-55443: 0.21% estimated exploitation activity in the next 30 days; percentile 11.27 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. We have no evidence of this behavior being…

Published by the source

16 Jun 2026, 15:03 UTC

Last modified by the source

10 Sep 2026, 03:51 UTC

Source last checked

26 Oct 2026, 13:46 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-gr75-jv2w-4656

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-gr75-jv2w-4656

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# Patch Next advisory brief: CVE-2026-55443

Advisory: LangChain: Path traversal and sandbox escape in LangChain file-search middleware and loaders
IDs: CVE-2026-55443, GHSA-gr75-jv2w-4656
Record: https://patchnext.com/advisories/cve-2026-55443 (revision 2, source checked 26 Oct 2026, 13:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: langchain 1.3.9; langchain-anthropic 1.4.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI langchain: affected <= 1.3.8; fixed in 1.3.9
- PyPI langchain-anthropic: affected <= 1.4.5; fixed in 1.4.6

## Suggested inspection (read-only)
- `python -m pip show langchain`: prints the installed version. Run with the environment that serves production active.
- `python -m pip show langchain-anthropic`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on langchain, langchain-anthropic.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-gr75-jv2w-4656 (OSV record GHSA-gr75-jv2w-4656 lists affected ranges: PyPI langchain >=0 =0 <1.4.6 (fixed))
- Verified: https://github.com/advisories/GHSA-gr75-jv2w-4656 (GitHub-reviewed advisory GHSA-gr75-jv2w-4656 lists affected ranges: PyPI langchain >=0 =0 <=1.4.5)

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