DeepSeek’s web chat interface appears to be leaking conversations between accounts. When opening the chat, a user encountered chat histories that did not belong to them, suggesting a session isolation failure on DeepSeek’s servers.

Privacy incident

If confirmed, this represents a severe data leak where user chat data is being exposed across sessions. Users are advised to avoid entering sensitive information into DeepSeek chat until the issue is resolved.

Evidence

A recording shows the leak in action:

The video demonstrates opening DeepSeek chat and being presented with what appears to be another user’s conversation history, including prompts and responses that the account holder did not create.

What to do

If you use DeepSeek chat, avoid sharing personal, financial, or confidential information until DeepSeek issues a statement. Clear your chat history and consider using alternative services for sensitive conversations.