LangChain Community: redirect chaining can lead to SSRF bypass via RecursiveUrlLoader

CISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.

No exploitation or prediction data is available here for these CVEs. This does not mean they are safe or unlikely to be exploited.

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.

Source published

25 Feb 2026 17:30:01 UTC

Source modified

25 Feb 2026 18:42:52 UTC

Saved here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

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

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.

Source published

Feb 25, 2026, 5:30:01 PM (timezone not stated)

Source modified

Feb 25, 2026, 6:42:52 PM (timezone not stated)

Saved here

13 Nov 2026 15:59:18 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

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

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.

Source published

25 Feb 2026 18:23:41 UTC

Source modified

17 Jun 2026 10:27:41 UTC

Saved here

25 Oct 2026 06:17:33 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · [email protected] · Secondary · 4.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N

CVSS 3.1 · [email protected] · Primary · 7.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N

## Summary 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). ## Affected Component - Package: `@langchain/community` - Component: `RecursiveUrlLoader` - Configuration: `preventOutside` (default: `true`) is insufficient to prevent this bypass when redirects are followed automatically. ## Description `RecursiveUrlLoader` is a web crawler that recursively follows links from a starting URL. The existing SSRF mitigation validates the initial URL before fetching, but it does not re-validate when the request follows redirects. Because fetch follows redirects by default, an attacker can supply a public URL that passes validation and then redirects to a private network address, localhost, or cloud metadata endpoint. This constitutes a “check‑then‑act” gap in the request lifecycle: the safety check occurs before the redirect chain is resolved, and the final destination is never validated. ## Impact If an attacker can influence content on a page being crawled (e.g., user‑generated content, untrusted external pages), they can cause the crawler to: - Fetch cloud instance metadata (AWS, GCP, Azure), potentially exposing credentials or tokens - Access internal services on private networks (`10.x`, `172.16.x`, `192.168.x`) - Connect to localhost services - Exfiltrate response data through attacker-controlled redirect chains This is exploitable in any environment where `RecursiveUrlLoader` runs with access to internal networks or metadata services, which includes most cloud-hosted deployments. ## Attack Scenario 1. The crawler is pointed at a public URL that passes initial SSRF validation. 2. That URL responds with a 3xx redirect to an internal target. 3. The fetch follows the redirect automatically without revalidation. 4. The crawler accesses the internal or metadata endpoint. Example redirector: ``` https://302.r3dir.me/--to/?url=http://169.254.169.254/latest/meta-data/ ``` ## Root Cause - SSRF validation (`validateSafeUrl`) is only performed on the initial URL. - Redirects are followed automatically by fetch (`redirect: "follow"` default), so the request can change destinations without additional validation. ## Resolution Upgrade to `@langchain/community` **>= 1.1.18**, which validates every redirect hop by disabling automatic redirects and re-validating `Location` targets before following them. - Automatic redirects are disabled (`redirect: "manual"`). - Each 3xx `Location` is resolved and validated with `validateSafeUrl()` before the next request. - A maximum redirect limit prevents infinite loops. ## Reources - Original SSRF fix (CVE-2026-26019): enforced origin comparison and added initial URL validation - https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-gf3v-fwqg-4vh7

Source published

25 Feb 2026 22:59:48 UTC

Source modified

10 Sep 2026 03:50:35 UTC

Saved here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N

Publisher rating · MODERATE