CVE-2026-27795
LangChain Community: redirect chaining can lead to SSRF bypass via RecursiveUrlLoader
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.
INFO
Published Date :
Feb. 25, 2026, 6:23 p.m.
Last Modified :
April 13, 2026, 2:15 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Upgrade to `@langchain/community` version 1.1.18.
- Ensure redirects are validated before following.
- Implement a maximum redirect limit.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-27795.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-27795 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-27795
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-27795 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-27795 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Apr. 13, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N Added CPE Configuration OR *cpe:2.3:a:langchain:langchain_community:*:*:*:*:*:node.js:*:* versions up to (excluding) 1.1.18 Added Reference Type GitHub, Inc.: https://github.com/langchain-ai/langchainjs/commit/2812d2b2b9fd9343c4850e2ab906b8cf440975ee Types: Patch Added Reference Type GitHub, Inc.: https://github.com/langchain-ai/langchainjs/commit/d5e3db0d01ab321ec70a875805b2f74aefdadf9d Types: Patch Added Reference Type GitHub, Inc.: https://github.com/langchain-ai/langchainjs/pull/9990 Types: Issue Tracking Added Reference Type GitHub, Inc.: https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.14 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.18 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7 Types: Not Applicable Added Reference Type GitHub, Inc.: https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-mphv-75cg-56wg Types: Vendor Advisory -
New CVE Received by [email protected]
Feb. 25, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N Added CWE CWE-918 Added Reference https://github.com/langchain-ai/langchainjs/commit/2812d2b2b9fd9343c4850e2ab906b8cf440975ee Added Reference https://github.com/langchain-ai/langchainjs/commit/d5e3db0d01ab321ec70a875805b2f74aefdadf9d Added Reference https://github.com/langchain-ai/langchainjs/pull/9990 Added Reference https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.14 Added Reference https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.18 Added Reference https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7 Added Reference https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-mphv-75cg-56wg