CVE-2026-54311: n8n: Merge Node SQL Mode Prototype Pollution
Impact An authenticated user with permission to create or modify workflows could pollute the sandbox used by the Merge node's SQL Query mode. Because the sandbox context was cached and reused across all workflow executions on the instance, prototype mutations introduced by one user's workflow persist into subsequent Merge SQL executions belonging to other users or projects. This allowed a low-privileged attacker to intercept workflow data processed by other users on the same instance.
This issue only affects multi-user n8n instances where more than one user has permission to create and execute workflows containing the Merge node in SQL Query mode.
Patches The issue has been fixed in n8n versions 2.25.7, and 2.26.2. Users should upgrade to one of these versions or later to remediate the vulnerability.
Workarounds If upgrading is not immediately possible, administrators should consider the following temporary mitigations: - Limit workflow creation and editing permissions to fully trusted users only. - Disable the Merge node by adding n8n-nodes-base.merge to the NODESEXCLUDE environment variable.
These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.
Other sources
n8n is an open source workflow automation platform. Prior to 2.25.7 and 2.26.2, an authenticated user with permission to create or modify workflows could pollute the sandbox used by the Merge node's SQL Query mode. Because the sandbox context was cached and reused across all workflow executions on the instance, prototype mutations introduced by one user's workflow persist into subsequent Merge SQL executions belonging to other users or projects. This allowed a low-privileged attacker to intercept workflow data processed by other users on the same instance. This issue only affects multi-user n8n instances where more than one user has permission to create and execute workflows containing the Merge node in SQL Query mode. This vulnerability is fixed in 2.25.7 and 2.26.2.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/n8nto a version that resolves this vulnerability.Fixed in 2.25.7 - Upgrade
Upgrade
npm/n8nto a version that resolves this vulnerability.Fixed in 2.26.2 - Upgrade
Upgrade
n8nto a version that resolves this vulnerability.Fixed in 2.25.7 - Upgrade
Upgrade
n8nto a version that resolves this vulnerability.Fixed in 2.26.2 - Configuration
Temporarily mitigate by disabling the Merge node: add `n8n-nodes-base.merge` to the `NODES_EXCLUDE` environment variable.
n8n Merge node NODES_EXCLUDE = n8n-nodes-base.merge - Configuration
Temporarily mitigate by limiting workflow creation and editing permissions to fully trusted users only (for multi-user instances where users can create/modify workflows containing the Merge node in SQL Query mode).
n8n permissions workflow creation/editing permissions = fully trusted users only - Compensating control
If you cannot upgrade immediately, use only the listed temporary mitigations (disable the Merge node via `NODES_EXCLUDE`, and restrict workflow creation/editing permissions to fully trusted users) until upgrading to 2.25.7 or 2.26.2 is possible.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-54311?
The severity of CVE-2026-54311 is classified as medium with a score of 6.3.
How do I fix CVE-2026-54311?
To fix CVE-2026-54311, ensure that the software is updated to the latest version that patches the vulnerability.
What impact does CVE-2026-54311 have on my system?
CVE-2026-54311 allows an authenticated user to potentially pollute the sandbox of the Merge node's SQL Query mode.
Who is affected by CVE-2026-54311?
CVE-2026-54311 affects users of npm/n8n who have permissions to create or modify workflows.
What kind of attack does CVE-2026-54311 facilitate?
CVE-2026-54311 could facilitate a sandbox pollution attack through manipulated workflows by authenticated users.