Cyber Resilience

CVE-2026-42235

High

Published: 04 May 2026

Published
04 May 2026
Modified
06 May 2026
KEV Added
—
Patch
—
CVSS Score v4 8.8 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0033 25.1th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-42235 is a high-severity Cross-site Scripting (CWE-79) vulnerability in N8N N8N. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique JavaScript (T1059.007); ranked at the 25.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as AI Agent Protocols and Integrations; in the Protocol-Specific Risks risk domain.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)
CWE-79CWE-87

AI Security AnalysisAI

AI Category
AI Agent Protocols and Integrations
Risk Domain
Protocol-Specific Risks
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: mcp

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1059.007 JavaScript Execution
Adversaries may abuse various implementations of JavaScript for execution.
attack.mitre.org →
T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
attack.mitre.org →
T1539 Steal Web Session Cookie Credential Access
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.
attack.mitre.org →
T1552 Unsecured Credentials Credential Access
Adversaries may search compromised systems to find and obtain insecurely stored credentials.
attack.mitre.org →
Why these techniques?

Stored XSS enables arbitrary JS execution in authenticated browser session, directly facilitating session hijacking, cookie theft, credential access, and subsequent manipulation/escalation.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

Affected Assets

n8n
n8n
2.18.0 · ≤ 1.123.32 · 2.17.0 — 2.17.4

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

SI-10 Information Input Validation
addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

SI-15 Information Output Filtering
addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

References