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

published 2026-09-23 46 d ago modified 2026-09-24 46 d ago also EUVD-2026-85508

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits: 0; none known

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.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 46 d ago (2026-09-24)

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Affected products

Cinnamon AI Kotaemon

Classification

Weakness

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

References

Sources

CVE List CVE-2026-86867
NVD CVE-2026-86867

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Summary