CVE-2026-110842: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') in n8n-io n8n
Description
n8n versions before 2.41.4 and 2.42.x before 2.42.1 contain a prototype pollution vulnerability in the MCP workflow-validation tool. This flaw allows an authenticated user with only workflow:read permission to manipulate shared prototypes, bypassing server-side permission checks and potentially taking over owner accounts without MFA protection.
CVSS v4.0
Score 7.7high
Affected software
n8n-io
n8n
pkg:github/n8n-io/n8nRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-110842 is a prototype pollution vulnerability in n8n's MCP workflow-validation tool. The interpreter evaluates caller-supplied code in the main process, reads inherited properties, and permits assignment onto shared prototypes. An authenticated user with minimal permissions (workflow:read) can replace built-in methods with ones returning truthy values, causing permission checks to accept scopes the user does not hold. This enables escalation to owner account takeover if MFA is not enabled.
Potential Impact
The vulnerability allows privilege escalation from a low-privilege authenticated user to owner-level access by bypassing permission checks. This can lead to full account takeover of owner accounts lacking multi-factor authentication, compromising the integrity and security of the affected n8n instance.
Mitigation Recommendations
Upgrade n8n to version 2.41.4 or later, or to 2.42.1 or later for the 2.42.x branch, where this vulnerability is fixed. No other mitigations are indicated. Patch status is confirmed by the affected version ranges.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-10-14T22:12:22.055Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ad00a612cdf04f656ba025c
Added to database: 10/14/2026, 23:04:01 UTC
Last enriched: 10/14/2026, 23:33:15 UTC
Last updated: 10/14/2026, 23:33:15 UTC
Views: 5
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