CVE-2026-42235
Critical · 9.6CVSS
9.6
EPSS
0.5%
Published
May 4, 2026
CISA due date
—
The record
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.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| npm | n8n | 0 | 1.123.32 |
| npm | n8n | 2.17.0 | 2.17.4 |
| npm | n8n | 2.18.0 | 2.18.1 |
Related vulnerabilities
- GHSA-537j-gqpc-p7fq n8n Vulnerable to XSS via MCP OAuth client Same vulnerability
- CVE-2026-54308 n8n is an open source workflow automation platform. Also affects n8n
- CVE-2026-54307 n8n is an open source workflow automation platform. Also affects n8n
- CVE-2026-54304 n8n is an open source workflow automation platform. Also affects n8n
- CVE-2026-54305 n8n is an open source workflow automation platform. Also affects n8n
- CVE-2026-54306 n8n is an open source workflow automation platform. Also affects n8n
- CVE-2026-54302 n8n is an open source workflow automation platform. Also affects n8n
- CVE-2026-54301 n8n is an open source workflow automation platform. Also affects n8n