Khoj is a self-hostable artificial intelligence app. Prior to 2.0.0-beta.23, an IDOR in the Notion OAuth callback allows an attacker to hijack any user's Notion integration by manipulating the state parameter. The callback endpoint accepts any user UUID without verifying the OAuth flow was initiated by that user, allowing attackers to replace victims' Notion configurations with their own, resulting in data poisoning and unauthorized access to the victim's Khoj search index. This attack requires knowing the user's UUID which can be leaked through shared conversations where an AI generated image is present. This vulnerability is fixed in 2.0.0-beta.23.

Affected: PyPI: khoj

### Summary An IDOR in the Notion OAuth callback allows an attacker to hijack any user's Notion integration by manipulating the state parameter. The callback endpoint accepts any user UUID without verifying the OAuth flow was initiated by that user, allowing attackers to replace victims' Notion configurations with their own, resulting in data poisoning and unauthorized access to the victim's Khoj search index.

This attack requires knowing the user's UUID which can be leaked through shared conversations where an AI generated image is present.

### Details When users share conversations which contain AI generated images, the file path for the image is constructed using the user's UUID. Knowing this UUID, an attacker is able to intercept the OAuth callback for Notion and replace the `state` parameter with the other user's UUID and sync notion onto their account.

### PoC

The vulnerable line of code exists in `src/khoj/routers/notion.py` on the callback endpoint. ```python @notion_router.get("/auth/callback") async def notion_auth_callback(request: Request, background_tasks: BackgroundTasks): code = request.query_params.get("code") state = request.query_params.get("state") # <-- Attacker controlled if not code or not state: return Response("Missing code or state", status_code=400)

user: KhojUser = await aget_user_by_uuid(state) # <-- No verification!

await NotionConfig.objects.filter(user=user).adelete() # <-- Deletes victim's config #…

Affected: PyPI: khoj

### Summary An IDOR in the Notion OAuth callback allows an attacker to hijack any user's Notion integration by manipulating the state parameter. The callback endpoint accepts any user UUID without verifying the OAuth flow was initiated by that user, allowing attackers to replace victims' Notion configurations with their own, resulting in data poisoning and unauthorized access to the victim's Khoj search index.

This attack requires knowing the user's UUID which can be leaked through shared conversations where an AI generated image is present.

### Details When users share conversations which contain AI generated images, the file path for the image is constructed using the user's UUID. Knowing this UUID, an attacker is able to intercept the OAuth callback for Notion and replace the `state` parameter with the other user's UUID and sync notion onto their account.

### PoC

The vulnerable line of code exists in `src/khoj/routers/notion.py` on the callback endpoint. ```python @notion_router.get("/auth/callback") async def notion_auth_callback(request: Request, background_tasks: BackgroundTasks): code = request.query_params.get("code") state = request.query_params.get("state") # <-- Attacker controlled if not code or not state: return Response("Missing code or state", status_code=400)

user: KhojUser = await aget_user_by_uuid(state) # <-- No verification!

await NotionConfig.objects.filter(user=user).adelete() # <-- Deletes victim's config #…