Langchain Community
CVE-2026-27795
MEDIUM
Severity by source
AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N
Lifecycle Timeline
3Blast Radius
ecosystem impact- 50 npm packages depend on @langchain/community (2 direct, 48 indirect)
Ecosystem-wide dependent count for version 1.1.18.
DescriptionGitHub Advisory
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.
AnalysisAI
LangChain's RecursiveUrlLoader in @langchain/community versions prior to 1.1.18 fails to validate redirect targets, allowing authenticated attackers to bypass SSRF protections by redirecting from whitelisted URLs to internal or metadata endpoints. An attacker with user credentials can exploit this to access sensitive internal resources or cloud metadata services through automatic redirect following. Affected applications should upgrade to version 1.1.18, which disables automatic redirects and re-validates each redirect destination.
Technical ContextAI
This vulnerability (CWE-918: Server-Side Request Forgery (SSRF)) affects LangChain is a framework for building LLM-powered applications.. 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). Use
RemediationAI
Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.
More in Langchain Community
View allSame weakness CWE-918 – Server-Side Request Forgery (SSRF)
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External POC / Exploit Code
Leaving vuln.today
GHSA-mphv-75cg-56wg