CVE-2026-26019
MEDIUM
GHSA-gf3v-fwqg-4vh7
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N
Lifecycle Timeline
3Description
LangChain is a framework for building LLM-powered applications. Prior to 1.1.14, 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, 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, localhost, or RFC 1918 addresses, and the crawler would fetch them without restriction. This vulnerability is fixed in 1.1.14.
Analysis
RecursiveUrlLoader in LangChain Community prior to 1.1.14 uses weak string-based URL validation that allows attackers to bypass the preventOutside crawling restriction by crafting domains with matching prefixes, potentially exposing the crawler to malicious or internal infrastructure endpoints. An attacker controlling a crawled webpage could inject links to cloud metadata services or private IP ranges, which the crawler would follow without validation, leading to information disclosure.
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Remediation
Within 30 days: Identify affected systems running is a framework for building LLM-powered applications. and apply vendor patches as part of regular patch cycle. …
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