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CVE-2026-42235— n8n: XSS via MCP OAuth client

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n8n开源的一个可扩展的工作流自动化工具。 n8n 1.123.32之前版本、2.17.4之前版本和2.18.1之前版本存在跨站脚本漏洞，该漏洞源于未经身份验证的攻击者可注册恶意MCP OAuth客户端并包含特制client_name，可能导致受害者用户授权后第二个用户撤销访问时渲染注入脚本，点击链接执行任意JavaScript，实现凭据和会话令牌窃取、工作流操纵或权限提升。

AI Predicted 8.2 Difficulty: Moderate EPSS 0.51% · P41

Affected Version Matrix 3

VendorProduct Version RangeStatus
n8n-io n8n < 1.123.32 affected
>= 2.17.0, < 2.17.4 affected
>= 2.18.0, < 2.18.1 affected
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I. Basic Information for CVE-2026-42235

Vulnerability Information
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Vulnerability Title
n8n: XSS via MCP OAuth client
Source: CVE Program / CVE List V5
Vulnerability Description
n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, an unauthenticated attacker could register a malicious MCP OAuth client with a crafted client_name. If a victim user authorized the OAuth consent dialog and a second user subsequently revoked that access, a toast notification would render the injected script. Clicking the link would execute arbitrary JavaScript in the victim's authenticated n8n browser session, enabling credential and session token theft, workflow manipulation, or privilege escalation. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L
Source: CVE Program / CVE List V5
Vulnerability Type
替代XSS语法转义处理不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
n8n 跨站脚本漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
n8n是n8n开源的一个可扩展的工作流自动化工具。 n8n 1.123.32之前版本、2.17.4之前版本和2.18.1之前版本存在跨站脚本漏洞，该漏洞源于未经身份验证的攻击者可注册恶意MCP OAuth客户端并包含特制client_name，可能导致受害者用户授权后第二个用户撤销访问时渲染注入脚本，点击链接执行任意JavaScript，实现凭据和会话令牌窃取、工作流操纵或权限提升。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
n8n-io n8n < 1.123.32 -

II. Public POCs for CVE-2026-42235

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III. Intelligence Information for CVE-2026-42235

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Vendor Advisories for CVE-2026-42235 (1)

Same Patch Batch · n8n-io · 2026-05-04 · 12 CVEs total

CVE-2026-42232 n8n: XML Node Prototype Pollution to RCE
CVE-2026-42233 n8n: SQL Injection in Oracle Database Node via Limit Field
CVE-2026-42229 n8n: SQL Injection in SeaTable Node
CVE-2026-42228 n8n: Hijacking of Unauthenticated Chat Execution
CVE-2026-42236 n8n: Unauthenticated Denial of Service via MCP Client Registration
CVE-2026-42237 n8n: SQL Injection in Snowflake and MySQL Nodes
CVE-2026-42226 n8n: Credential Authorization Bypass in dynamic-node-parameters Allows Foreign API Key Rep
CVE-2026-42230 n8n: Open Redirect in MCP OAuth Consent Flow
CVE-2026-42234 n8n: Python Task Runner Sandbox Escape
CVE-2026-42227 n8n: Public API Variables IDOR Allows Cross-Project Secret Disclosure
CVE-2026-42231 n8n: Prototype Pollution in XML Webhook Body Parser Leads to RCE

IV. Related Vulnerabilities

Same product: n8n
Same vendor: n8n-io
Same weakness: CWE-87

V. Comments for CVE-2026-42235

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