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CVE-2026-42235

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

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 8.8 · High · EPSS 0.3% · Fix available

Published
Updated

Stack: node

Affected products and versions

  • n8n

    Versions
    • < 1.123.32: Affected
    • >= 2.17.0, < 2.17.4: Affected
    • >= 2.18.0, < 2.18.1: Affected

    No fix published

  • n8n npm

    Affected ranges
    • SEMVER: < 1.123.32

    Update to 1.123.32

  • n8n npm

    Affected ranges
    • SEMVER: ≥ 2.18.0, < 2.18.1

    Update to 2.18.1

  • n8n npm

    Affected ranges
    • SEMVER: ≥ 2.17.0, < 2.17.4

    Update to 2.17.4

Original sources

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