CVE-2026-65702: falha de alta gravidade em vanna-ai vanna

Vanna through 2.0.2 contains a path traversal vulnerability in the FileSystemConversationStore persistence integration that allows unauthenticated remote attackers to write attacker-controlled JSON files to arbitrary filesystem locations and read conversation metadata from outside the intended store base directory. Attackers can supply path traversal sequences in the conversation_id parameter submitted to the unauthenticated chat API endpoints to escape the base directory during both write and read operations, enabling arbitrary file write with attacker-controlled content and unauthorized file read on the server filesystem.