{"id":"CVE-2026-42230","aliases":["EUVD-2026-27100","GHSA-f6x8-65q6-j9m9"],"status":"published","title":"n8n: Open Redirect in MCP OAuth Consent Flow","description":"n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the /mcp-oauth/register endpoint accepted OAuth client registrations without authentication, allowing arbitrary redirect_uri values to be registered. When a user denies the MCP OAuth consent dialog, the handleDeny handler redirects the user to the registered redirect_uri without validation, enabling an open redirect to an attacker-controlled URL. An attacker can craft a phishing link and send it to a victim; if the victim clicks \"Deny\" on the consent page, they are silently redirected to an external site. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.","severity":{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00181,"percentile":0.07761,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-601"],"published":"2026-04-29T21:10:17Z","modified":"2026-10-28T02:30:48Z","fixes":[{"ecosystem":"npm","package":"n8n","fixed_in":["1.123.32","2.18.1","2.17.4"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"n8n","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.123.32"}]}]},{"source":"ghsa","ecosystem":"npm","package":"n8n","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.18.0"},{"fixed":"2.18.1"}]}]},{"source":"ghsa","ecosystem":"npm","package":"n8n","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.0.0"},{"fixed":"2.17.4"}]}]},{"source":"osv","ecosystem":"npm","package":"n8n","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.123.32"}]}]},{"source":"osv","ecosystem":"npm","package":"n8n","ranges":[{"type":"SEMVER","events":[{"introduced":"2.18.0"},{"fixed":"2.18.1"}]}]},{"source":"osv","ecosystem":"npm","package":"n8n","ranges":[{"type":"SEMVER","events":[{"introduced":"2.0.0"},{"fixed":"2.17.4"}]}]}],"products":[{"vendor":"n8n","product":"n8n"},{"vendor":"n8n-io","product":"n8n"}],"references":[{"url":"https://github.com/n8n-io/n8n/security/advisories/GHSA-f6x8-65q6-j9m9","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42230","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-f6x8-65q6-j9m9"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42230.json","tags":["advisory"]},{"url":"https://github.com/n8n-io/n8n","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-42230","title":"n8n: Open Redirect in MCP OAuth Consent Flow","description":"n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the /mcp-oauth/register endpoint accepted OAuth client registrations without authentication, allowing arbitrary redirect_uri values to be registered. When a user denies the MCP OAuth consent dialog, the handleDeny handler redirects the user to the registered redirect_uri without validation, enabling an open redirect to an attacker-controlled URL. An attacker can craft a phishing link and send it to a victim; if the victim clicks \"Deny\" on the consent page, they are silently redirected to an external site. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.","status":"published","published":"2026-05-04T18:28:43.069Z","modified":"2026-05-04T19:56:27.611Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T13:40:35.004553Z"}],"euvd":[{"id":"EUVD-2026-27100","description":"n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the /mcp-oauth/register endpoint accepted OAuth client registrations without authentication, allowing arbitrary redirect_uri values to be registered. When a user denies the MCP OAuth consent dialog, the handleDeny handler redirects the user to the registered redirect_uri without validation, enabling an open redirect to an attacker-controlled URL. An attacker can craft a phishing link and send it to a victim; if the victim clicks \"Deny\" on the consent page, they are silently redirected to an external site. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.","status":"published","published":"2026-05-04T18:28:43Z","modified":"2026-05-04T19:56:27Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T19:05:17.549765Z"}],"ghsa":[{"id":"GHSA-f6x8-65q6-j9m9","title":"n8n has Open Redirect in MCP OAuth Consent Flow","description":"## Impact\nThe `/mcp-oauth/register` endpoint accepted OAuth client registrations without authentication, allowing arbitrary `redirect_uri` values to be registered. When a user denies the MCP OAuth consent dialog, the `handleDeny` handler redirects the user to the registered `redirect_uri` without validation, enabling an open redirect to an attacker-controlled URL. An attacker can craft a phishing link and send it to a victim; if the victim clicks \"Deny\" on the consent page, they are silently redirected to an external site.\n\n## Patches\nThe issue has been fixed in n8n versions 1.123.32, 2.17.4, and 2.18.1. Users should upgrade to one of these versions or later to remediate the vulnerability.\n\n## Workarounds\nIf upgrading is not immediately possible, administrators should consider the following temporary mitigations:\n- Restrict network access to the n8n instance to prevent untrusted users from reaching the MCP OAuth endpoints.\n- Limit access to the n8n instance to fully trusted users only.\n\nThese workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.","status":"published","published":"2026-04-29T21:10:17Z","modified":"2026-05-08T01:30:47Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N","level":"medium"},{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T14:40:03.762927Z"}],"nvd":[{"id":"CVE-2026-42230","description":"n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the /mcp-oauth/register endpoint accepted OAuth client registrations without authentication, allowing arbitrary redirect_uri values to be registered. When a user denies the MCP OAuth consent dialog, the handleDeny handler redirects the user to the registered redirect_uri without validation, enabling an open redirect to an attacker-controlled URL. An attacker can craft a phishing link and send it to a victim; if the victim clicks \"Deny\" on the consent page, they are silently redirected to an external site. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.","status":"published","published":"2026-05-04T19:16:05.237Z","modified":"2026-06-17T10:47:32.967Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T14:12:17.022502Z"}],"osv":[{"id":"CVE-2026-42230","title":"n8n: Open Redirect in MCP OAuth Consent Flow","description":"n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the /mcp-oauth/register endpoint accepted OAuth client registrations without authentication, allowing arbitrary redirect_uri values to be registered. When a user denies the MCP OAuth consent dialog, the handleDeny handler redirects the user to the registered redirect_uri without validation, enabling an open redirect to an attacker-controlled URL. An attacker can craft a phishing link and send it to a victim; if the victim clicks \"Deny\" on the consent page, they are silently redirected to an external site. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.","status":"published","published":"2026-05-04T18:28:43.069Z","modified":"2026-10-28T02:30:48.540851987Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N","level":"medium"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T15:45:04.117819Z"},{"id":"GHSA-f6x8-65q6-j9m9","title":"n8n has Open Redirect in MCP OAuth Consent Flow","description":"## Impact\nThe `/mcp-oauth/register` endpoint accepted OAuth client registrations without authentication, allowing arbitrary `redirect_uri` values to be registered. When a user denies the MCP OAuth consent dialog, the `handleDeny` handler redirects the user to the registered `redirect_uri` without validation, enabling an open redirect to an attacker-controlled URL. An attacker can craft a phishing link and send it to a victim; if the victim clicks \"Deny\" on the consent page, they are silently redirected to an external site.\n\n## Patches\nThe issue has been fixed in n8n versions 1.123.32, 2.17.4, and 2.18.1. Users should upgrade to one of these versions or later to remediate the vulnerability.\n\n## Workarounds\nIf upgrading is not immediately possible, administrators should consider the following temporary mitigations:\n- Restrict network access to the n8n instance to prevent untrusted users from reaching the MCP OAuth endpoints.\n- Limit access to the n8n instance to fully trusted users only.\n\nThese workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.","status":"published","published":"2026-04-29T21:10:17Z","modified":"2026-05-08T01:49:37.039376Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","level":"medium"},{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N","level":"medium"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T15:46:46.006631Z"}]}}