Cinnamon's kotaemon contains improper authorization checks in multi‑user chat handlers

Cinnamon's Kotaemon (all versions up to and including v0.12.0) multi-user chat interface contains multiple vulnerabilities due to incorrect authorization and improper access controls. There are four handler methods in `libs/ktem/ktem/pages/chat/control.py` that load a Conversation record by its ID without comparing the requester's `user_id` to the conversation's owner `Conversation.user`. This allows any authenticated user to perform the following actions: 1. Read other user's chat transcripts, RAG retrieval history, AI-generated plots, and chat suggestions. 2. Permanently delete another user's conversation. 3. Rename another user's conversation. 4. Overwrite another user's conversation's chat suggestion list.

Kotaemon Missing Ownership Check in Conversation Functions

Kotaemon through 0.12.0 fails to properly validate conversation ownership in select_conv, delete_conv, rename_conv, and on_set_public_conversation functions in control.py. Attackers can read other users' chat histories, delete conversations, or rename conversations by supplying arbitrary conversation identifiers without proper authorization checks.

kotaemon 0.12.0 Unauthenticated Remote Code Execution via Insecure Deserialization

kotaemon through 0.12.0 contains an insecure deserialization vulnerability in the check_connection endpoint that allows unauthenticated attackers to instantiate arbitrary Python classes by supplying crafted YAML/JSON input with a __type__ field. Attackers can exploit this to override the __type__ field with subprocess.check_output and arbitrary arguments, achieving remote code execution with application process privileges.

An issue was discovered in Cinnamon kotaemon 0.11.0. The _may_extract_zip function in the \libs\ktem\ktem\index\file\ui.py file does not check the contents of uploaded ZIP files. Although the contents are extracted into a temporary folder that is cleared before each extraction, successfully uploading a ZIP bomb could still cause the server to consume excessive resources during decompression. Moreover, if no further files are uploaded afterward, the extracted data could occupy disk space and potentially render the system unavailable. Anyone with permission to upload files can carry out this attack.

Plaintext password storage in Kotaemon 0.11.0 in the client's localStorage.

Cross site scripting (XSS) vulnerability in Kotaemon 0.11.0 allowing attackers to execute arbitrary code via a crafted PDF.