CVE-2026-118641 in n8n
Summary
by MITRE • 10/28/2026
n8n before 1.123.85, 2.x before 2.43.5, and 2.44.x before 2.44.1 contains an OData $filter injection vulnerability in the Microsoft Outlook contact lookup and Microsoft SharePoint v1 item update nodes, which build $filter string literals from expression-bindable parameters without escaping. Attackers who supply untrusted input to such workflows can inject single quotes to dump the bound mailbox's entire contact list or redirect SharePoint writes onto unintended list items within the stored credential's scope.
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Analysis
by VulDB Data Team • 10/28/2026
The vulnerability identified in n8n versions prior to 1.123.85, 2.x before 2.43.5, and 2.44.x before 2.44.1 represents a critical injection flaw within the platform's integration nodes for Microsoft Outlook contacts and SharePoint items. This security issue stems from an OData $filter injection vulnerability that arises when these specific workflow components construct query strings using expression-bindable parameters without adequate sanitization or escaping of user-supplied input. In automated workflows, it is common practice to pass dynamic values into API calls to filter data based on runtime variables; however, in this instance, the framework fails to properly escape special characters such as single quotes within these expressions before they are incorporated into the OData query structure. This lack of proper encoding allows malicious actors who can control or influence the input parameters of a workflow to manipulate the resulting SQL-like query syntax used by Microsoft's APIs.
From a technical perspective, the core flaw lies in the construction of $filter string literals where untrusted data is directly concatenated into the query without validation against injection patterns. OData filters rely on specific syntactic rules for parsing conditions, and single quotes are often used to delimit string values within these queries. By injecting additional single quotes or logical operators through crafted input, an attacker can break out of the intended filter context and append arbitrary commands or modify existing logic. This behavior is characteristic of CWE-94 Improper Control of Generation of Code SQL Injection, specifically adapted for OData query languages which share similar injection vectors with traditional database queries. The vulnerability exploits the trust placed in workflow inputs by assuming they are benign when interacting with external services like Microsoft 365 and SharePoint Online.
The operational impact of this vulnerability is severe due to its potential for unauthorized data access and unintended state modification. For the Microsoft Outlook contact lookup node, an attacker can exploit the injection point to dump the entire contact list associated with the mailbox bound by the workflow's credentials. This results in a significant confidentiality breach, exposing sensitive personal or professional information stored within organizational directories. Similarly, for the SharePoint v1 item update node, the vulnerability allows attackers to redirect write operations onto unintended list items. By manipulating the filter logic that identifies which record should be updated, an attacker can overwrite data belonging to other users or systems within the scope of the compromised credentials. This leads to integrity violations and potential denial of service through corrupted data states, affecting the reliability of business processes dependent on accurate SharePoint records.
This vulnerability aligns with MITRE ATT&CK techniques related to Data Injection and potentially Account Manipulation if used for persistent access via modified configurations. It highlights the risks associated with low-code automation platforms where complex logic is abstracted away from developers who might otherwise implement robust input validation. The attack vector typically requires initial access to configure or trigger a workflow, which may be achieved through social engineering, compromised credentials, or exploitation of other vulnerabilities in the n8n instance itself. Once inside, the ability to exfiltrate large volumes of contact data or alter critical business records underscores the importance of treating all input parameters as untrusted until proven otherwise.
Mitigation strategies must prioritize immediate upgrading to patched versions of n8n that address this specific injection flaw by implementing proper escaping mechanisms for OData filter expressions. Organizations relying on these integrations should also implement strict access controls and principle of least privilege when configuring service accounts used within workflows, ensuring that even if an injection occurs, the scope of damage is limited. Additionally, input validation layers should be introduced at the workflow design level to restrict allowable characters in fields intended for API queries. Security monitoring tools should be configured to detect anomalous query patterns originating from n8n instances, particularly those involving unusual combinations of quotes or logical operators in outbound HTTP requests to Microsoft endpoints. Regular audits of workflow configurations can help identify nodes that accept dynamic input without corresponding sanitization logic, thereby reducing the attack surface for future exploitation attempts.