CVE-2026-69098: Unauthenticated Remote Code Execution in kotaemon via Insecure Deserialization

Executive Summary

A critical vulnerability, CVE-2026-69098, with a CVSS score of 9.8, was discovered in kotaemon through version 0.12.0. This vulnerability allows unauthenticated attackers to execute remote code by exploiting an insecure deserialization issue in the check_connection endpoint. The vulnerability is considered critical and requires immediate attention.

Technical Analysis

The vulnerability is classified as an insecure deserialization issue (CWE-502). The check_connection endpoint in kotaemon through 0.12.0 is vulnerable to insecure deserialization. An attacker can exploit this by supplying crafted YAML/JSON input with a __type__ field, allowing the instantiation of arbitrary Python classes. By overriding the __type__ field with subprocess.check_output and arbitrary arguments, an attacker can achieve remote code execution with application process privileges.

How It Gets Exploited

An unauthenticated remote attacker can send crafted YAML/JSON input to the check_connection endpoint. The input must contain a __type__ field that is used to instantiate arbitrary Python classes. By carefully crafting this input, an attacker can override the __type__ field to execute subprocess.check_output with arbitrary arguments. This results in remote code execution with the privileges of the application process. For example, an attacker might send a request with a malicious payload that, when deserialized, triggers the execution of system commands.

Impact Assessment

The affected product is kotaemon, specifically versions up to and including 0.12.0. An attacker exploiting CVE-2026-69098 can achieve remote code execution, which could lead to confidentiality, integrity, and availability impacts. The CVSS score of 9.8 indicates a critical severity level, emphasizing the need for immediate mitigation.

Recommended Actions

To mitigate this vulnerability, users of kotaemon should update to a version beyond 0.12.0. Additionally, implementing network segmentation, restricting access to the check_connection endpoint, and monitoring for suspicious traffic can help reduce the risk of exploitation. Detection guidance includes monitoring for unusual input to the check_connection endpoint and implementing WAF rules to block suspicious YAML/JSON payloads.

Sources

- National Vulnerability Database (NVD) - CVE-2026-69098 Details - kotaemon GitHub Repository - Vulncheck Advisory