CVE-2026-69098: Kotaemon RCE Vulnerability

CVE-2026-69098 Overview

CVE-2026-69098 is an insecure deserialization vulnerability in kotaemon through version 0.12.0. The flaw resides in the check_connection endpoint, which processes user-supplied YAML/JSON input containing a __type__ field. Unauthenticated attackers can leverage this field to instantiate arbitrary Python classes on the server. By setting __type__ to subprocess.check_output with attacker-controlled arguments, an adversary achieves remote code execution with the privileges of the application process. The issue is tracked under [CWE-502] Deserialization of Untrusted Data.

Critical Impact
Unauthenticated remote code execution against exposed kotaemon deployments allows full compromise of the application host and any data or credentials it can access.

Affected Products

kotaemon versions up to and including 0.12.0
Deployments exposing the check_connection endpoint
Self-hosted kotaemon retrieval-augmented generation (RAG) instances

Discovery Timeline

2026-08-04 - CVE-2026-69098 published to the National Vulnerability Database
2026-08-05 - Last updated in NVD database

Technical Details for CVE-2026-69098

Vulnerability Analysis

kotaemon is an open-source RAG interface for interacting with large language models over user documents. The check_connection endpoint accepts structured input in YAML or JSON. During processing, the application inspects the __type__ field and dynamically resolves it to a Python class, then instantiates that class with attacker-supplied arguments.

Because the endpoint requires no authentication, any network-reachable adversary can submit a crafted payload. Substituting subprocess.check_output for the expected type turns the deserialization routine into an arbitrary command execution primitive. The resulting process runs with the same privileges as the kotaemon service, granting access to configuration files, API keys, and connected data stores.

Root Cause

The root cause is unsafe type resolution during deserialization. The endpoint treats __type__ as a trusted class specifier without validating it against an allowlist of expected classes. Any importable Python callable, including subprocess helpers, becomes reachable through the deserializer.

Attack Vector

Exploitation requires a single HTTP request to the check_connection endpoint with a YAML or JSON body that sets __type__ to a dangerous callable such as subprocess.check_output. The remaining fields supply command arguments. No credentials, user interaction, or prior foothold are required. Refer to the VulnCheck Advisory for Kotaemon and the GitHub Issue Discussion for the disclosed proof-of-concept details.

Detection Methods for CVE-2026-69098

Indicators of Compromise

HTTP POST requests to check_connection containing a __type__ key referencing subprocess, os, builtins, or importlib modules.
Child processes spawned by the kotaemon application executing shells (sh, bash, cmd.exe) or reconnaissance binaries such as whoami, id, or curl.
Unexpected outbound network connections from the kotaemon host to attacker-controlled infrastructure.
New files written to the kotaemon working directory or /tmp shortly after requests to check_connection.

Detection Strategies

Inspect application access logs for requests to check_connection with YAML/JSON bodies containing __type__ tokens.
Correlate web request telemetry with process creation events on the kotaemon host to identify command execution triggered by HTTP traffic.
Deploy web application firewall rules that block deserialization payloads referencing dangerous Python callables in request bodies.

Monitoring Recommendations

Enable verbose logging on the kotaemon reverse proxy and archive request bodies for post-incident review.
Monitor for anomalous child processes of the Python interpreter running kotaemon using endpoint detection tooling.
Alert on outbound egress from the kotaemon host to non-approved destinations, including DNS lookups to newly observed domains.

How to Mitigate CVE-2026-69098

Immediate Actions Required

Restrict network exposure of kotaemon so the check_connection endpoint is not reachable from untrusted networks.
Place kotaemon behind an authenticating reverse proxy that rejects anonymous requests to configuration endpoints.
Audit the kotaemon host for signs of prior exploitation, including new shell sessions, cron jobs, and modified startup scripts.
Rotate any API keys, model provider tokens, and database credentials stored in the kotaemon configuration.

Patch Information

At the time of publication, no fixed release beyond 0.12.0 is referenced in the NVD entry. Track the upstream GitHub Issue Discussion and the VulnCheck Advisory for Kotaemon for updated patch guidance and apply fixes as soon as a maintained release is available.

Workarounds

Disable or remove the check_connection endpoint route until a patched version is deployed.
Run kotaemon as an unprivileged user inside an isolated container with read-only filesystem mounts to reduce blast radius.
Apply egress network policies that deny outbound connections from the kotaemon container except to required model provider endpoints.
Enforce request-body filtering at the reverse proxy to reject payloads containing __type__ fields referencing subprocess, os, or builtins.

bash

# Example nginx rule to block deserialization payloads targeting check_connection
location /check_connection {
    if ($request_body ~* "__type__.*(subprocess|os\.|builtins|importlib)") {
        return 403;
    }
    proxy_pass http://kotaemon_upstream;
}