CVE-2026-86078— n8n: Prototype Pollution via Workflow Structure Summary Can Lead to Denial of Service
Quick assessment
Affected
n8n-io n8n
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
n8n 是一个开源的工作流自动化平台。在 2.37.7 和 2.38.2 之前的版本中，实例 AI（Instance AI）的工作流摘要功能将从存储的工作流中获取的节点名称和连接键（connection keys）作为普通对象键使用。通过 REST API 提交的工作流可能包含 或 等保留键，从而导致嵌套写入操作能够影响到主 n8n 进程中的 ，进而干扰后续请求的正常处理。 受影响的函数是位于 中的 。 该问题已在版本 2.37.7 和 2.38.2 中修复。
Possible ATT&CK Techniques 3 AI
T1059 · Command and Scripting Interpreter T1557 · Adversary-in-the-Middle T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-86078
Vulnerability Information
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Vulnerability Title
n8n: Prototype Pollution via Workflow Structure Summary Can Lead to Denial of Service
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
CWE-1321
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-86078
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-86078 (1)
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🔗 Release n8n@2.38.2 · n8n-io/n8n · GitHub x_refsource_MISC
Vendor Advisories for CVE-2026-86078 (1)
Vendor Pages for CVE-2026-86078 (1)
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🔗 Release n8n@2.37.7 · n8n-io/n8n · GitHub x_refsource_MISC
Same Patch Batch · n8n-io · 2026-09-08 · 17 CVEs total
| CVE-2026-86076 | 8.7 HIGH | n8n: Expression Sandbox Escape in Editor-UI Enables Stored Cross-User JavaScript Execution |
| CVE-2026-86075 | 8.7 HIGH | n8n: Unauthenticated Persistent Storage Exhaustion via OAuth Dynamic Client Registration E |
| CVE-2026-86083 | 7.7 HIGH | n8n: Expression Sandbox Escape via Shared Builtin Tampering and Code-Printer Injection Lea |
| CVE-2026-86082 | 7.1 HIGH | n8n: Domain-Restriction Bypass via Unguarded Model-Search Endpoint in OpenAI Chat Model No |
| CVE-2026-86081 | 7.1 HIGH | n8n: Regular Expression Denial of Service in the Default Blocked-File-Pattern Match via a |
| CVE-2026-86077 | 6.3 MEDIUM | n8n: Anonymous Approval-Gate Bypass via Reused resumeToken over the Chat WebSocket |
| CVE-2026-86080 | 6.3 MEDIUM | n8n: GitHub Trigger 422 Reuse Path Skips Webhook Secret Storage, Causing Signature Verific |
| CVE-2026-86079 | 6.3 MEDIUM | n8n: Path Injection in Elasticsearch and ElasticSecurity Nodes via Unencoded Identifiers |
| CVE-2026-86084 | 6.0 MEDIUM | n8n: Disabled OIDC SSO Endpoints Remain Active and Issue Valid Sessions |
| CVE-2026-86073 | 5.9 MEDIUM | n8n: Per-Resource OAuth Consent Bypass via Unbound Refresh Token Resource Substitution |
| CVE-2026-86074 | 5.9 MEDIUM | n8n: Instance AI Credential Setup Accepts Unvalidated Probe URL from Fetched Content |
| CVE-2026-86993 | 5.9 MEDIUM | n8n: Log Streaming Event Destinations Decrypt Generic-Auth Credentials Without Ownership C |
| CVE-2026-86994 | 5.3 MEDIUM | n8n: Cross-User Active Workflow ID and Lifecycle Event Disclosure via Missing userId Filte |
| CVE-2026-86995 | 5.3 MEDIUM | n8n: Git Node branch.<name>.remote Config Key Bypasses Sandbox Path Restriction, Enabling |
| CVE-2026-86996 | 5.3 MEDIUM | n8n: Agent Workflow Tool Bypasses Sub-Workflow Caller Policy |
| CVE-2026-86085 | 5.1 MEDIUM | n8n: Cross-Tenant Project-Member PII Disclosure via Missing Per-Project Scope Check on Rol |
IV. Related Vulnerabilities
Same product: n8n
-
CVE-2026-86075
n8n: Unauthenticated Persistent Storage Exhaustion via OAuth -
CVE-2026-86076
n8n: Expression Sandbox Escape in Editor-UI Enables Stored C -
CVE-2026-86077
n8n: Anonymous Approval-Gate Bypass via Reused resumeToken o -
CVE-2026-86079
n8n: Path Injection in Elasticsearch and ElasticSecurity Nod -
CVE-2026-86080
n8n: GitHub Trigger 422 Reuse Path Skips Webhook Secret Stor
Same vendor: n8n-io
-
CVE-2026-86075
n8n: Unauthenticated Persistent Storage Exhaustion via OAuth -
CVE-2026-86076
n8n: Expression Sandbox Escape in Editor-UI Enables Stored C -
CVE-2026-86077
n8n: Anonymous Approval-Gate Bypass via Reused resumeToken o -
CVE-2026-86079
n8n: Path Injection in Elasticsearch and ElasticSecurity Nod -
CVE-2026-86080
n8n: GitHub Trigger 422 Reuse Path Skips Webhook Secret Stor
Same weakness: CWE-1321
-
CVE-2026-81994
Acrobat Reader | Improperly Controlled Modification of Objec -
CVE-2026-85625
sift 17.1.3 Prototype Pollution Remote Code Execution via $w -
CVE-2026-63376
toml-node: Prototype Pollution Leads to `Object.prototype` C -
CVE-2026-85063
node-csv: Prototype replacement still reachable via columns -
CVE-2026-82404
TOON: Prototype pollution when decoding untrusted TOON input
V. Comments for CVE-2026-86078
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