SSRF in Langchain Community
CVE-2026-27795
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.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.004 (29.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 29.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002
Affected products
- Langchain Community
- Langchain-Ai Langchainjs — versions < 1.1.18
Weakness classification (CWE)
References
- github.com/langchain-ai/langchainjs/security/advisories/GHSA-mphv-75cg-56wg (Vendor Advisory)
- github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7 (Not Applicable)
- github.com/langchain-ai/langchainjs/pull/9990 (Issue Tracking)
- github.com/langchain-ai/langchainjs/commit/2812d2b2b9fd9343c4850e2ab906b8cf4409… (Patch)
- github.com/langchain-ai/langchainjs/commit/d5e3db0d01ab321ec70a875805b2f74aefda… (Patch)
- github.com/langchain-ai/langchainjs/releases/tag/@langchain/community@1.1.14 (Release Notes)
- github.com/langchain-ai/langchainjs/releases/tag/@langchain/community@1.1.18 (Release Notes)
Frequently asked questions
- What is CVE-2026-27795?
- CVE-2026-27795 is a medium-severity vulnerability in Langchain Community, classified under Server-Side Request Forgery (SSRF). CVSS score: 4.1/10. Published 2026-02-25.
- How severe is CVE-2026-27795?
- Medium severity. CVSS v3 base score is 4.1 out of 10.