CVE-2024-2965 in LangChain
Summary
by MITRE • 06/06/2024
A Denial-of-Service (DoS) vulnerability exists in the `SitemapLoader` class of the `langchain-ai/langchain` repository, affecting all versions. The `parse_sitemap` method, responsible for parsing sitemaps and extracting URLs, lacks a mechanism to prevent infinite recursion when a sitemap URL refers to the current sitemap itself. This oversight allows for the possibility of an infinite loop, leading to a crash by exceeding the maximum recursion depth in Python. This vulnerability can be exploited to occupy server socket/port resources and crash the Python process, impacting the availability of services relying on this functionality.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 10/16/2024
The vulnerability described in CVE-2024-2965 represents a critical denial-of-service weakness within the langchain framework's sitemap processing capabilities. This issue resides in the SitemapLoader class where the parse_sitemap method fails to implement proper recursion detection mechanisms. The flaw specifically manifests when a sitemap contains a URL that references the same sitemap file, creating a circular dependency that the current implementation cannot handle gracefully. This design oversight allows attackers to craft malicious sitemap files that trigger infinite recursive calls, ultimately exhausting the Python interpreter's recursion limit and causing process termination. The vulnerability affects all versions of the langchain-ai/langchain repository, indicating a fundamental flaw in the library's architecture that has persisted across multiple releases.
The technical implementation of this vulnerability stems from the absence of cycle detection in the sitemap parsing algorithm. When the parse_sitemap method encounters a sitemap URL, it recursively processes each URL without maintaining a history of previously visited sitemaps or URLs. This lack of state tracking creates an environment where circular references can lead to unbounded recursion, as defined by CWE-674. The Python interpreter's default recursion limit of 1000 frames provides minimal protection against this specific attack vector, making it trivial for adversaries to construct sitemap structures that will inevitably crash the process. The operational impact extends beyond simple process termination, as the DoS condition can consume significant system resources during the recursive loop execution, potentially leading to resource exhaustion that affects overall system availability and service reliability.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1499.004 which focuses on network denial of service attacks. The exploitation mechanism demonstrates how seemingly benign functionality can be weaponized to create service disruption. The vulnerability's impact is particularly concerning for applications that rely on automated sitemap parsing for content discovery, web crawling, or indexing operations. When exploited, the vulnerability can cause cascading failures in systems where sitemap processing is part of automated workflows, potentially affecting multiple services that depend on the langchain library. The resource consumption pattern typical of such recursive DoS attacks can also be leveraged for indirect impact, as the process crashes may trigger additional system failures or require manual intervention to restore normal operations. Organizations using langchain components for web scraping, content analysis, or automated data ingestion are particularly at risk since these operations often occur in automated environments where such DoS conditions can persist undetected.
The recommended mitigation strategies include implementing explicit cycle detection mechanisms within the parse_sitemap method, maintaining a set of already-visited URLs or sitemap identifiers to prevent reprocessing. Additionally, establishing maximum recursion depth limits or iterative processing approaches can provide defense-in-depth measures against similar vulnerabilities. The fix should also incorporate proper error handling and logging to detect when circular references are encountered, allowing for graceful degradation rather than complete system failure. Security teams should also consider implementing rate limiting and input validation for sitemap processing to prevent abuse of this functionality. Regular security assessments of third-party libraries and dependencies should include analysis of recursion patterns and state management to prevent similar vulnerabilities from emerging in other components of the software ecosystem.