CVE-2026-26019 is a medium-severity (CVSS 4.1) Server-Side Request Forgery (SSRF) vulnerability in @langchain/community. A fix is available for @langchain/community — see the affected versions and patch details below.
@langchain/community affected by SSRF Bypass in RecursiveUrlLoader via insufficient URL origin validation
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-26019.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
@langchain/communitynpmDescription
Description
The RecursiveUrlLoader class in @langchain/community is a web crawler that recursively follows links from a starting URL. Its preventOutside option (enabled by default) is intended to restrict crawling to the same site as the base URL.
The implementation used String.startsWith() to compare URLs, which does not perform semantic URL validation. An attacker who controls content on a crawled page could include links to domains that share a string prefix with the target (e.g., https://example.com.attacker.com passes a startsWith check against https://example.com), causing the crawler to follow links to attacker-controlled or internal infrastructure.
Additionally, the crawler performed no validation against private or reserved IP addresses. A crawled page could include links targeting cloud metadata services (169.254.169.254), localhost, or RFC 1918 addresses, and the crawler would fetch them without restriction.
Impact
An attacker who can influence the content of a page being crawled (e.g., by placing a link on a public-facing page, forum, or user-generated content) could cause the crawler to:
- Fetch cloud instance metadata (AWS, GCP, Azure), potentially exposing IAM credentials and session tokens
- Access internal services on private networks (
10.x,172.16.x,192.168.x) - Connect to localhost services
- Exfiltrate response data via attacker-controlled redirect chains
This is exploitable in any environment where RecursiveUrlLoader runs on infrastructure with access to cloud metadata or internal services — which includes most cloud-hosted deployments.
Resolution
Two changes were made:
-
Origin comparison replaced. The
startsWithcheck was replaced with a strict origin comparison using the URL API (new URL(link).origin === new URL(baseUrl).origin). This correctly validates scheme, hostname, and port as a unit, preventing subdomain-based bypasses. -
SSRF validation added to all fetch operations. A new URL validation module (
@langchain/core/utils/ssrf) was introduced and applied before every outbound fetch in the crawler. This blocks requests to:- Cloud metadata endpoints:
169.254.169.254,169.254.170.2,100.100.100.200,metadata.google.internal, and related hostnames - Private IP ranges:
10.0.0.0/8,172.16.0.0/12,192.168.0.0/16,127.0.0.0/8,169.254.0.0/16 - IPv6 equivalents:
::1,fc00::/7,fe80::/10 - Non-HTTP/HTTPS schemes (
file:,ftp:,javascript:, etc.)
- Cloud metadata endpoints:
Cloud metadata endpoints are unconditionally blocked and cannot be overridden.
Workarounds
Users who cannot upgrade immediately should avoid using RecursiveUrlLoader on untrusted or user-influenced content, or should run the crawler in a network environment without access to cloud metadata or internal services.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @langchain/community | all versions | 1.1.14npm install @langchain/community@1.1.14 |
Affected Products
langchain communitylangchainDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @langchain/community, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @langchain/community to 1.1.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-26019 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.Source: Red Hat security advisory for CVE-2026-26019 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-26019 in your dependencies?
Find it across npm, including transitive dependencies.