CVE-2026-86867 Cinnamon's kotaemon contains improper authorization checks in multi‑user chat handlers
Authenticated users can read, delete, rename, or modify other users' chat conversations due to missing ownership checks in Kotaemon.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-86867?
CVE-2026-86867 is a medium-severity missing authorization vulnerability in Cinnamon AI Kotaemon, published on 23 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-86867?
How do I fix CVE-2026-86867?
No fix has been published for CVE-2026-86867 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-86867 being exploited?
There is no known exploitation of CVE-2026-86867 in the wild and no public exploit code.
Sources
Also known as GHSA-xj3r-7j9q-cqf2.