{"cve":"CVE-2026-42235","nvd":{"published":"2026-05-04T19:16:06.173","modified":"2026-06-17T10:47:33.523","status":"Analyzed","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.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L","score":8.8},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","score":9.6},"cwes":["CWE-79","CWE-87"],"references":["https://github.com/n8n-io/n8n/security/advisories/GHSA-537j-gqpc-p7fq"],"products":["n8n:n8n"],"source":"nvd","synced_at":"2026-10-19T22:33:09.003606135+00:00"},"epss":{"cve":"CVE-2026-42235","score":0.00332,"percentile":0.2643,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-537j-gqpc-p7fq","url":"https://osv.dev/vulnerability/GHSA-537j-gqpc-p7fq","summary":"n8n Vulnerable to XSS via MCP OAuth client","modified":"2026-05-08T01:48:43.684926Z","packages":[{"ecosystem":"npm","name":"n8n","purl":"pkg:npm/n8n","ranges":["<1.123.32"],"fixed":["1.123.32"]},{"ecosystem":"npm","name":"n8n","purl":"pkg:npm/n8n","ranges":[">=2.18.0 <2.18.1"],"fixed":["2.18.1"]},{"ecosystem":"npm","name":"n8n","purl":"pkg:npm/n8n","ranges":[">=2.17.0 <2.17.4"],"fixed":["2.17.4"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}