n8n EUVD-2026-112376

Exploitation requires a specific, non-default workflow design: a workflow that uses the Quick Base node's record:getAll (Get Many) or record:delete operation AND builds the 'Where' filter from untrusted external data (for example webhook payload) via an expression, which n8n passes to the Quick Base API as raw query text. Limiting factors: the n8n instance and the triggering workflow/webhook must be reachable by the attacker; a valid Quick Base credential must be stored in the workflow, and impact is bounded by that credential's privileges; the vulnerable path does not exist if the Where filter uses static values or the new 'Where Parameters' option instead of an expression over untrusted input. Per the vendor, using Where Parameters for dynamic values avoids the issue, while a Where filter built with an expression remains unsafe.

This is a genuine, prioritize-this-week issue rather than CVSS inflation, but its real-world risk is strongly gated by configuration. The provided CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:N/UI:N) with VC:N/VI:N/VA:N but SC:H/SI:H shows the n8n host itself suffers no direct confidentiality/integrity/availability loss; the high impact falls on the subsequent system - the connected Quick Base table - where an attacker can read or delete every record using the workflow credential's privileges. The AT:P (Attack Requirements: Present) flag is the key signal: exploitation is not universal but depends on a specific deployment pattern, namely a workflow that builds the Quick Base 'Where' filter from untrusted input such as webhook data via an expression. The vuln.today decision label is 'this_week', consistent with network-reachable, unauthenticated-trigger, high-data-impact but condition-dependent exploitation. No EPSS score, no CISA KEV listing, and no verified working exploit code were provided, so there is no evidence of active exploitation or mass-scanning probability - the risk is currently driven by severity and reachability, not observed exploitation. Signals are consistent rather than conflicting; the main caveat is that PR:N reflects the external webhook caller, while actually reaching a vulnerable state requires an administrator to have built an unsafe workflow, which the raw score does not convey.

An n8n workflow exposes a webhook that feeds caller-supplied data into a Quick Base node whose 'Where' filter is constructed from that input via an expression. A remote attacker sends a crafted webhook request that alters the filter logic so that a Get Many operation returns every row in the target Quick Base table, or a Delete operation removes every record, all executed with the stored workflow credential's privileges. No public, verified exploit code was identified in the provided data, but the technique is straightforward given the raw-query-text behavior described in the advisory.