CVE-2026-86078 n8n: Prototype Pollution via Workflow Structure Summary Can Lead to Denial of Service
Attackers can cause denial of service in n8n by submitting workflows with malicious keys that pollute the prototype, requiring an upgrade to fix.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-86078?
CVE-2026-86078 is a medium-severity vulnerability in N8n N8n, published on 8 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
n8n is an open source workflow automation platform. Prior to 2.37.7 and 2.38.2, the Instance AI workflow summary used node names and connection keys from stored workflows as ordinary object keys. A workflow submitted through the REST API could contain __proto__ or constructor, causing nested writes to reach Object.prototype in the main n8n process and disrupt later requests. The affected function is summarizeWorkflowStructure in packages/@n8n/instance-ai/src/tools/workflows/summarize-workflow.ts. This issue is fixed in versions 2.37.7 and 2.38.2.
Weakness: CWE-1321
Which versions are affected by CVE-2026-86078?
4 open source packages ship an affected version, including n8n. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
n8n npm | All versions | 2.37.7 |
n8n npm | All versions | 2.37.7 |
n8n npm | From 2.38.0 | 2.38.2 |
n8n npm | From 2.38.0 | 2.38.2 |
Products include N8n N8n.
How do I fix CVE-2026-86078?
Upgrade n8n to a fixed version for your release line: 2.37.7 or 2.38.2.
Is CVE-2026-86078 being exploited?
There is no known exploitation of CVE-2026-86078 in the wild and no public exploit code.
Other vulnerabilities in N8n N8n
- CVE-2025-68613 n8n Improper Control of Dynamically-Managed Code Resources
- CVE-2026-21877 n8n is vulnerable to Remote Code Execution via Arbitrary File Write
- CVE-2026-21858 n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling
- CVE-2026-1470 n8n Unsafe Workflow Expression Evaluation Allows Remote Code Execution
- CVE-2025-68668 n8n Vulnerable to Arbitrary Command Execution in Pyodide based Python Code Node
Sources
Also known as GHSA-679f-58pq-4v2c, MINI-2xqh-6wch-52vm.