CVE-2026-42235: CWE-87: Improper Neutralization of Alternate XSS Syntax in n8n-io n8n
CVE-2026-42235 is a high-severity vulnerability in the n8n workflow automation platform affecting versions prior to 1. 123. 32, 2. 17. 4, and 2. 18. 1. It allows an unauthenticated attacker to register a malicious OAuth client with a crafted client_name that leads to cross-site scripting (XSS) when a victim user authorizes the OAuth consent and another user revokes access, triggering a toast notification that executes arbitrary JavaScript. This can result in credential and session token theft, workflow manipulation, or privilege escalation. The issue has been patched in the specified fixed versions.
AI Analysis
Technical Summary
This vulnerability involves improper neutralization of alternate XSS syntax (CWE-87) in n8n's OAuth client registration process. An attacker can register a malicious OAuth client with a specially crafted client_name. When a victim user authorizes this client and a second user revokes access, a toast notification renders the injected script, which executes in the victim's authenticated browser session. This enables attackers to steal credentials, session tokens, manipulate workflows, or escalate privileges. The vulnerability affects n8n versions before 1.123.32, 2.17.4, and 2.18.1 and has been fixed in these versions.
Potential Impact
Successful exploitation allows execution of arbitrary JavaScript in the context of an authenticated n8n user session. This can lead to theft of credentials and session tokens, unauthorized manipulation of workflows, and privilege escalation within the n8n platform. The CVSS 4.0 score is 8.8 (high severity), reflecting network attack vector, low attack complexity, partial user interaction, and high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
A fix is available and has been released in n8n versions 1.123.32, 2.17.4, and 2.18.1. Users should upgrade to these or later versions to remediate the vulnerability. No additional vendor advisory details on temporary mitigations are provided. Patch status is confirmed by the vendor's versioning information in the description.
CVE-2026-42235: CWE-87: Improper Neutralization of Alternate XSS Syntax in n8n-io n8n
Description
CVE-2026-42235 is a high-severity vulnerability in the n8n workflow automation platform affecting versions prior to 1. 123. 32, 2. 17. 4, and 2. 18. 1. It allows an unauthenticated attacker to register a malicious OAuth client with a crafted client_name that leads to cross-site scripting (XSS) when a victim user authorizes the OAuth consent and another user revokes access, triggering a toast notification that executes arbitrary JavaScript. This can result in credential and session token theft, workflow manipulation, or privilege escalation. The issue has been patched in the specified fixed versions.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves improper neutralization of alternate XSS syntax (CWE-87) in n8n's OAuth client registration process. An attacker can register a malicious OAuth client with a specially crafted client_name. When a victim user authorizes this client and a second user revokes access, a toast notification renders the injected script, which executes in the victim's authenticated browser session. This enables attackers to steal credentials, session tokens, manipulate workflows, or escalate privileges. The vulnerability affects n8n versions before 1.123.32, 2.17.4, and 2.18.1 and has been fixed in these versions.
Potential Impact
Successful exploitation allows execution of arbitrary JavaScript in the context of an authenticated n8n user session. This can lead to theft of credentials and session tokens, unauthorized manipulation of workflows, and privilege escalation within the n8n platform. The CVSS 4.0 score is 8.8 (high severity), reflecting network attack vector, low attack complexity, partial user interaction, and high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
A fix is available and has been released in n8n versions 1.123.32, 2.17.4, and 2.18.1. Users should upgrade to these or later versions to remediate the vulnerability. No additional vendor advisory details on temporary mitigations are provided. Patch status is confirmed by the vendor's versioning information in the description.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-25T05:37:12.117Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69f8eab1cbff5d8610415b90
Added to database: 5/4/2026, 6:51:29 PM
Last enriched: 5/4/2026, 7:06:25 PM
Last updated: 5/4/2026, 7:55:26 PM
Views: 7
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.