n8n CVE-2026-54312

Exploitation requires an authenticated account on the target n8n instance that holds permission to create or modify workflows (PR:L per the vendor CVSS 4.0 vector); no end-user interaction or social engineering is needed (UI:N, AT:N). The specific feature involved is the Microsoft SQL node 'n8n-nodes-base.microsoftSql' - instances that have disabled this node via NODES_EXCLUDE are not vulnerable through this path. The attacker must reach the n8n HTTP API/UI over the network (AV:N), but no special deployment mode beyond a default installation that has not been upgraded to 2.24.0 is required.

The vendor CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:H) with base score 7.2 emphasizes high availability impact and low privileges, which aligns with a self-service DoS by any workflow author. There is no CISA KEV listing, no EPSS data supplied, and no public exploit identified at time of analysis, so this is not a mass-exploitation priority. Real risk is highest for multi-tenant or community n8n deployments where workflow-edit permissions are granted broadly - in those environments a single malicious or careless user can knock the whole instance offline until restart. For single-operator self-hosted deployments the practical risk is low because the attacker must already be a trusted workflow author. Confidentiality/integrity impacts are rated Low by the vendor, but the description does not describe any data exfiltration mechanism, so the dominant concrete impact is availability.

A user holding workflow-edit rights on a shared n8n instance (for example, a SaaS-style internal deployment with multiple team members) creates a workflow containing a Microsoft SQL node, supplies a crafted 'table' parameter that walks into Object.prototype, and executes the workflow once. From that moment every subsequent object in the Node.js process inherits the polluted property, causing validation routines across n8n to fail and rendering the UI and API unusable until an administrator restarts the service.