External risk intelligence

Kotaemon Insecure Deserialization Remote Code Execution

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2026-69098

The vulnerability exists in a web application endpoint accessible without authentication. Kotaemon is an open-source RAG web interface typically deployed as a service for users to interact with documents, making its web endpoints commonly exposed in network-accessible or public-facing deployment patterns.

Deserialization

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This vulnerability in kotaemon allows unauthenticated attackers to execute arbitrary code by sending specially crafted input. This could potentially lead to unauthorized access and control over the application's environment. The main concern is confirming relevance and exposure.

Attackers can run unauthorized code.
It affects web endpoints, often exposed externally.
Confirm if this technology is in use.

Attack Path

How an attacker could exploit the issue

An attacker can target an exposed web endpoint to send specially crafted data. This data, when processed by the application, can lead to the execution of arbitrary commands on the system.

No authentication required.
Send crafted YAML/JSON input.
Remote code execution with application privileges.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow unauthenticated attackers to execute arbitrary Python code on systems running kotaemon when the `check_connection` endpoint is exposed. This could occur if an attacker sends specially crafted YAML or JSON input, leading to the execution of commands with the privileges of the application's process.

System data and service behavior may be affected.
Unauthenticated input can trigger arbitrary code execution.
Remote code execution can compromise the application.

Operational Fix

Recommended remediation, mitigation, and detection steps

This critical deserialization vulnerability primarily impacts application owners and platform teams responsible for the kotaemon deployment. The immediate priority is to identify all instances of the affected technology, confirm its network exposure and business criticality, and then assign an owner for remediation planning.

Identify affected application instances.
Verify network reachability and business impact.
Plan remediation with accountable owners.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is kotaemon?

Kotaemon is an open-source web interface designed for Retrieval-Augmented Generation (RAG). Users typically deploy it as a service to interact with and query large document collections using LLMs. It functions as the bridge between your data and natural language processing models.

What does CWE-502 mean for CVE-2026-69098?

CWE-502, or Insecure Deserialization, happens when software takes untrusted data and uses it to reconstruct an object without validation. In this CVE, the application processes specially crafted YAML or JSON input that includes a __type__ field. Because the system trusts this input, an attacker can trick it into running arbitrary Python commands instead of just reading the intended data.

How is the check_connection endpoint triggered?

An attacker triggers the vulnerability by sending a malicious payload to the specific check_connection endpoint. This action does not require valid login credentials. Note that simply viewing the application or navigating to other pages does not trigger the flaw; it specifically requires submitting crafted input designed to instantiate unauthorized Python classes.

Is my kotaemon instance at risk?

According to Halo Surface Signal, you should be concerned if your instance is accessible over a network, especially if it is internet-facing. Because this vulnerability is reachable without authentication, any deployment where the web interface is exposed to a broader network—rather than restricted to local-only access—carries a high risk of remote compromise.

How do I respond to this vulnerability?

Start by locating every instance of kotaemon running in your environment. Once identified, evaluate whether each deployment is accessible over the network. Prioritize restricting access to the check_connection endpoint or the entire application for any instances reachable by unauthorized users while you plan a formal remediation path with your platform team.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.