CVE-2026-110842 n8n before 2.41.4 and 2.42.1 Prototype Pollution via MCP Workflow-Validation Interpreter
Authenticated users can exploit prototype pollution in the MCP interpreter to bypass permission checks and take over owner accounts.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-110842?
CVE-2026-110842 is a high-severity code injection vulnerability in n8n-io n8n, published on 14 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
n8n before 2.41.4 and 2.42.x before 2.42.1 contains a prototype pollution vulnerability in the MCP workflow-validation tool, whose interpreter evaluates caller-supplied code in the main process, reads inherited properties, and permits assignment onto shared prototypes. An authenticated member holding only a workflow:read grant can replace a built-in method with one returning a truthy value so server-side permission checks accept unheld scopes, enabling takeover of owner accounts not protected by MFA.
Weakness: CWE-1321
Which versions are affected by CVE-2026-110842?
How do I fix CVE-2026-110842?
No fix has been published for CVE-2026-110842 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-110842 being exploited?
There is no known exploitation of CVE-2026-110842 in the wild and no public exploit code.
Sources
Also known as GHSA-5jr4-xmvf-frmj, GHSA-fm6v-qhr5-4c32.