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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.

PUBLISHED Reserved 2026-02-24 | Published 2026-02-25 | Updated 2026-02-25 | Assigner GitHub_M




MEDIUM: 4.1CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N

Problem types

CWE-918: Server-Side Request Forgery (SSRF)

Product status

< 1.1.18
affected

References

github.com/...hainjs/security/advisories/GHSA-mphv-75cg-56wg

github.com/...hainjs/security/advisories/GHSA-gf3v-fwqg-4vh7

github.com/langchain-ai/langchainjs/pull/9990

github.com/...ommit/2812d2b2b9fd9343c4850e2ab906b8cf440975ee

github.com/...ommit/d5e3db0d01ab321ec70a875805b2f74aefdadf9d

github.com/...ainjs/releases/tag/@langchain/community@1.1.14

github.com/...ainjs/releases/tag/@langchain/community@1.1.18

cve.org (CVE-2026-27795)

nvd.nist.gov (CVE-2026-27795)

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