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 improper neutralization of alternate XSS syntax. When a victim user authorizes the OAuth consent and another user revokes access, a toast notification renders injected script, enabling execution of arbitrary JavaScript in the victim's authenticated session. This can result in credential and session token theft, workflow manipulation, or privilege escalation.
AI Analysis
Technical Summary
This vulnerability involves improper neutralization of alternate cross-site scripting (XSS) syntax (CWE-87) in n8n's OAuth client registration process. An attacker can register a malicious OAuth client with a crafted client_name that, upon specific user interactions (authorization followed by revocation), triggers a toast notification rendering injected JavaScript. This script executes in the context of the victim's authenticated browser session, potentially allowing theft of credentials and session tokens, manipulation of workflows, or escalation of privileges. The vulnerability affects n8n versions before 1.123.32, 2.17.4, and 2.18.1 and has been addressed in these versions.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary JavaScript in the victim's authenticated n8n session, leading to credential and session token theft, workflow manipulation, and privilege escalation. This compromises the confidentiality and integrity of the affected system and user data.
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 this vulnerability. No additional vendor advisory content is provided, so patching is the primary recommended mitigation.
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 improper neutralization of alternate XSS syntax. When a victim user authorizes the OAuth consent and another user revokes access, a toast notification renders injected script, enabling execution of arbitrary JavaScript in the victim's authenticated session. This can result in credential and session token theft, workflow manipulation, or privilege escalation.
CVSS v4.0
Score 8.8high
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves improper neutralization of alternate cross-site scripting (XSS) syntax (CWE-87) in n8n's OAuth client registration process. An attacker can register a malicious OAuth client with a crafted client_name that, upon specific user interactions (authorization followed by revocation), triggers a toast notification rendering injected JavaScript. This script executes in the context of the victim's authenticated browser session, potentially allowing theft of credentials and session tokens, manipulation of workflows, or escalation of privileges. The vulnerability affects n8n versions before 1.123.32, 2.17.4, and 2.18.1 and has been addressed in these versions.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary JavaScript in the victim's authenticated n8n session, leading to credential and session token theft, workflow manipulation, and privilege escalation. This compromises the confidentiality and integrity of the affected system and user data.
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 this vulnerability. No additional vendor advisory content is provided, so patching is the primary recommended mitigation.
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: 5/12/2026, 6:25:34 AM
Last updated: 6/18/2026, 9:59:47 PM
Views: 99
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