# 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.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Sep 2026
- **Updated:** 24 Sep 2026
- **Also known as:** GHSA-xj3r-7j9q-cqf2

## 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.

Weakness: CWE-862 (Missing Authorization), CWE-639 (Authorization Bypass Through User-Controlled Key), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## 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.

## Is CVE-2026-86867 being exploited?

There is no known exploitation of CVE-2026-86867 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-86867 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-86867 in the wild and no public exploit code.

Affected product: Cinnamon AI Kotaemon. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-86867/ (Markdown: https://insights.sbomify.com/CVE-2026-86867/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-86867
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-86867
- OSV: https://osv.dev/vulnerability/CVE-2026-86867

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-86867/
Summaries are generated and may contain mistakes; the official description above is the record.