CVE-2026-103258 in n8n
Summary
by MITRE • 10/01/2026
n8n versions before 2.39.6 and 2.40.0 before 2.40.1 contain an unescaped parameter interpolation vulnerability in SendGrid, Freshservice, and ServiceNow nodes that allows attackers to bypass filters by breaking out of query literals. Attackers can exploit this by binding vulnerable node parameters to untrusted external input to widen single-record lookups into match-all queries, exposing bulk data including contact lists, tickets, and directory entries.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability identified in n8n versions prior to 2.39.6 and the 2.40.x series before version 2.40.1 represents a critical server-side injection flaw rooted in improper handling of user-supplied input within specific workflow integration nodes. This issue specifically affects the SendGrid, Freshservice, and ServiceNow integrations, which are commonly used for email marketing, IT service management, and enterprise resource planning respectively. The core technical defect lies in the parameter interpolation mechanism employed by these nodes when constructing API requests or database queries against external services. When a workflow designer binds a node parameter to an expression that resolves from untrusted external input, such as data passed via webhooks or HTTP triggers, the system fails to properly escape special characters within those values before they are embedded into query literals. This lack of sanitization allows malicious actors to inject syntax that alters the logical structure of the underlying request, effectively breaking out of intended single-record lookups and transforming them into broad match-all queries.
From a technical perspective, this flaw aligns with CWE-94 Improper Control of Generation of Code or SQL Injection, specifically manifesting as an injection via parameter interpolation rather than direct code execution. The vulnerability enables attackers to manipulate the filtering criteria applied by the target service APIs. By injecting characters such as asterisks or wildcards that are interpreted broadly by the respective API engines, an attacker can bypass restrictive filters designed to limit data retrieval to a specific identifier. For instance, in SendGrid, this could allow the extraction of entire contact lists rather than details for a single subscriber. In Freshservice and ServiceNow, it permits the enumeration of all tickets or directory entries associated with an account, regardless of access controls that might normally restrict visibility based on user roles or ticket ownership. This exploitation technique is consistent with ATT&CK tactic T1078 Valid Accounts and sub-technique T1539 Attempt to Steal Web Session Credentials if the exposed data includes authentication tokens, but more broadly it falls under T1213 Data from Information Repositories as it involves extracting structured data from managed services.
The operational impact of this vulnerability is severe due to the sensitive nature of the data typically processed by these platforms. SendGrid contains email addresses and engagement metrics for marketing campaigns; Freshservice holds incident reports, customer details, and internal IT infrastructure information; ServiceNow stores comprehensive enterprise configuration items, employee records, and service request histories. An attacker exploiting this flaw can achieve unauthorized bulk access to proprietary business intelligence and personally identifiable information without needing elevated privileges within the target services themselves, relying instead on the misconfigured workflow parameters in n8n. This constitutes a significant data breach risk, potentially violating regulations such as GDPR or CCPA depending on the jurisdiction and nature of the exposed data. The ability to widen lookups from single-record retrieval to full dataset extraction means that even minimal exposure points can lead to massive data exfiltration events if left unpatched.
Mitigation strategies must prioritize immediate remediation through version upgrades, as this is a code-level defect requiring vendor intervention. Organizations running n8n should upgrade to version 2.39.6 or later for the stable branch and version 2.40.1 or later for the latest release line immediately upon availability. In environments where upgrading is not instantly feasible, temporary mitigations involve strict input validation on all external data sources that feed into these specific nodes. Workflow designers should avoid binding untrusted inputs directly to filter parameters in SendGrid, Freshservice, and ServiceNow nodes without implementing intermediate sanitization steps or using hardcoded safe values for critical lookups. Additionally, monitoring API logs from the integrated services for unusual patterns of bulk retrieval operations can help detect exploitation attempts in real-time. Long-term security posture improvements include adopting a principle of least privilege for workflow integrations and regularly auditing n8n workflows to ensure that no external inputs are directly interpolated into query structures without proper escaping or validation mechanisms.