LangSmith Bug Could Expose OpenAI Keys and User Data via Malicious Agents
Jun 17, 2025
Vulnerability / LLM Security
Cybersecurity researchers have disclosed a now-patched security flaw in LangChain's LangSmith platform that could be exploited to capture sensitive data, including API keys and user prompts. The vulnerability, which carries a CVSS score of 8.8 out of a maximum of 10.0, has been codenamed AgentSmith by Noma Security. LangSmith is an observability and evaluation platform that allows users to develop, test, and monitor large language model (LLM) applications, including those built using LangChain. The service also offers what's called a LangChain Hub , which acts as a repository for all publicly listed prompts, agents, and models. "This newly identified vulnerability exploited unsuspecting users who adopt an agent containing a pre-configured malicious proxy server uploaded to 'Prompt Hub,'" researchers Sasi Levi and Gal Moyal said in a report shared with The Hacker News. "Once adopted, the malicious proxy discreetly intercepted all user communicatio...
