CVE-2026-42235

n8n Vulnerable to XSS via MCP OAuth client

Published 4 May 2026Modified 17 Jun 2026CWE 79, 87

In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

NVD9.6CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

GHSA8.8CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L

Trivy's own label is CRITICAL. Rated critical by NVD. Rated lower by GHSA (high).

Description

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 and fixed versions

Source	Package	Fixed in
npm::GitHub Security Advisory npm	n8n	1.123.32, 2.18.1, 2.17.4

References

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FindsEvery admitted image is rescanned every 24 hours by default (scan.rescanInterval). When Trivy rates this vulnerability critical for the image's package source, it appears in the image's findings by name. Findings without a fix are left out unless includeUnfixed is on.
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RefusesWith a policy that blocks critical findings, a pod with this image is refused at admission, a rollback to it included. Pods already running are not evicted.
RecordsEach decision is recorded with the policy that ran and its hash, then sealed under a signed checkpoint.

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Vulnerability data compiled from the Trivy vulnerability database (trivy-db, Aqua Security, Apache License 2.0), which aggregates third-party advisories. CVE records are published by The MITRE Corporation under the CVE Terms of Use; CVE is a trademark of MITRE. This product uses data from the NVD API but is not endorsed or certified by the NVD. Severity, titles and advisory data from the GitHub Advisory Database (CC BY 4.0), Red Hat security data (CC BY 4.0) and the other sources linked on each entry. Entries may be summarised or re-formatted; the linked original is the authoritative record.