CVE-2026-103250 in n8n
Summary
by MITRE • 10/01/2026
n8n versions before 1.123.80, from 2.0.0 before 2.39.6, and from 2.40.0 before 2.40.1 contain a NoSQL injection vulnerability in the MongoDB Chat Memory node that fails to validate the sessionId parameter. Unauthenticated attackers can supply MongoDB query operators in the sessionId field to access conversation histories from other users and perform unauthorized write and delete operations.
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Analysis
by VulDB Data Team • 10/02/2026
The identified security flaw resides within n8n, a popular workflow automation platform, specifically affecting versions prior to 1.123.80, as well as the ranges between 2.0.0 and 2.39.6, and from 2.40.0 up to but not including 2.40.1. This vulnerability is classified as a NoSQL injection issue located in the MongoDB Chat Memory node, which is responsible for managing conversation states within automated workflows involving chat interfaces or AI integrations. The core technical deficiency stems from an insufficient validation mechanism applied to the sessionId parameter passed by users during workflow execution. Instead of sanitizing input or enforcing strict type checking, the application directly interpolates this user-supplied value into MongoDB query operations without adequate safeguards against maliciously crafted payloads containing NoSQL operators such as $gt, $ne, or $regex.
This architectural oversight allows unauthenticated attackers to exploit the lack of input validation by injecting specific MongoDB query syntax into the sessionId field. By doing so, an attacker can manipulate the underlying database queries to bypass intended access controls and data isolation boundaries. The operational impact is severe, as it enables unauthorized actors to retrieve conversation histories belonging to other users, leading to a significant breach of confidentiality and privacy. Furthermore, because the vulnerability extends beyond read operations, attackers are also capable of performing unauthorized write and delete actions against the database. This capability compromises data integrity by allowing malicious modification or destruction of stored workflow states and chat logs, potentially disrupting ongoing automation processes and corrupting critical business logic dependent on accurate historical context.
From a classification perspective, this vulnerability aligns with CWE-943, which describes Improper Neutralization of Special Elements used in an NoSQL Query, highlighting the failure to properly sanitize user-controlled input before its use in database queries. In terms of tactical mapping within the MITRE ATT&CK framework, this exploit scenario corresponds to T1059.027, representing Command and Scripting Interpreter usage via JavaScript or similar environments often utilized in web application attacks, specifically focusing on data exfiltration through unauthorized access (T1530) and potential impact on availability or integrity if destructive operations are executed. The attack vector is primarily network-based with no authentication required, making it particularly dangerous for public-facing instances of n8n that expose the Chat Memory node endpoints to external traffic without robust perimeter defenses.
To mitigate this risk, organizations running affected versions must immediately upgrade n8n to version 1.123.80 or later, ensuring they are also above version 2.39.6 if on the v2 branch, and specifically update to at least version 2.40.1 for those in the newer release track. These updated versions contain patches that enforce strict validation rules on the sessionId parameter, preventing the injection of NoSQL operators. In addition to upgrading software components, administrators should implement network-level access controls such as firewalls or reverse proxies to restrict exposure of n8n instances to trusted IP ranges only. It is also advisable to review existing workflows for any custom code nodes that might interact with MongoDB directly and apply similar input validation principles there. Regular security audits and the use of static application security testing tools can help identify similar injection vulnerabilities in other parts of the automation infrastructure before they are exploited in production environments.