CVE-2026-27795
Description
LangChain is a framework for building LLM-powered applications. Prior to version 1.1.8, a redirect-based Server-Side Request Forgery (SSRF) bypass exists in `RecursiveUrlLoader` in `@langchain/community`. The loader validates the initial URL but allows the underlying fetch to follow redirects automatically, which permits a transition from a safe public URL to an internal or metadata endpoint without revalidation. This is a bypass of the SSRF protections introduced in 1.1.14 (CVE-2026-26019). Users should upgrade to `@langchain/community` 1.1.18, which validates every redirect hop by disabling automatic redirects and re-validating `Location` targets before following them. In this version, automatic redirects are disabled (`redirect: "manual"`), each 3xx `Location` is resolved and validated with `validateSafeUrl()` before the next request, and a maximum redirect limit prevents infinite loops.
How to fix
- langchain langchain_community1.1.18 or later
- @langchain/community1.1.18 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| langchain langchain_community | v < 1.1.18 | 1.1.18 |
| @langchain/communitynpm | v < 1.1.18 | 1.1.18 |
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Attack Surface Management
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