# CVE-2026-27795: LangChain Community: redirect chaining can lead to SSRF bypass via RecursiveUrlLoader

> CVE-2026-27795: LangChain Community: redirect chaining can lead to SSRF bypass via RecursiveUrlLoader. CVSS 4.1 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-27795
Last updated: 2026-06-17T10:27:41Z

- Published: 2026-02-25 17:30 UTC · Updated: 2026-06-17 10:27 UTC · Assigner: GitHub\_M
- CVSS: 4.1 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N
- EPSS: 0.25%, 16th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-918

## 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.

## Affected vendors and products

- langchain-ai: langchainjs

## Tracked companies

- [LangChain (LangSmith)](https://rewindex.com/company/langchain-langsmith.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-27795)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-27795)
- [https://github.com/langchain-ai/langchainjs/commit/2812d2b2b9fd9343c4850e2ab906b8cf440975ee](https://github.com/langchain-ai/langchainjs/commit/2812d2b2b9fd9343c4850e2ab906b8cf440975ee)
- [https://github.com/langchain-ai/langchainjs/commit/d5e3db0d01ab321ec70a875805b2f74aefdadf9d](https://github.com/langchain-ai/langchainjs/commit/d5e3db0d01ab321ec70a875805b2f74aefdadf9d)
- [https://github.com/langchain-ai/langchainjs/pull/9990](https://github.com/langchain-ai/langchainjs/pull/9990)
- [https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.14](https://github.com/langchain-ai/langchainjs/releases/tag/%2540langchain%252Fcommunity%25401.1.14)
- [https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcommunity%401.1.18](https://github.com/langchain-ai/langchainjs/releases/tag/%2540langchain%252Fcommunity%25401.1.18)
- [https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7](https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7)
- [https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-mphv-75cg-56wg](https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-mphv-75cg-56wg)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-27795 · Markdown: https://rewindex.com/cve/CVE-2026-27795.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-27795 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:11:00.025Z