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Vulnerability details: VCID-ejke-qxks-u3gc
Vulnerability ID VCID-ejke-qxks-u3gc
Aliases CVE-2026-42235
GHSA-537j-gqpc-p7fq
Summary n8n Vulnerable to XSS via MCP OAuth client ## Impact 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. ## Patches This issue has been fixed in n8n version 2.14.2. Users should upgrade to this version or later to remediate the vulnerability. ## Workarounds If upgrading is not immediately possible, administrators should consider the following temporary mitigations: - Restrict access to the n8n instance and the MCP OAuth registration endpoint to trusted users only. - Disable MCP server functionality if it is not actively required. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (4)
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-87 Improper Neutralization of Alternate XSS Syntax
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.00115 https://api.first.org/data/v1/epss?cve=CVE-2026-42235
epss 0.00115 https://api.first.org/data/v1/epss?cve=CVE-2026-42235
cvssv3.1 8.2 https://github.com/n8n-io/n8n
cvssv4 8.8 https://github.com/n8n-io/n8n
generic_textual HIGH https://github.com/n8n-io/n8n
cvssv3.1 8.2 https://github.com/n8n-io/n8n/security/advisories/GHSA-537j-gqpc-p7fq
cvssv4 8.8 https://github.com/n8n-io/n8n/security/advisories/GHSA-537j-gqpc-p7fq
generic_textual HIGH https://github.com/n8n-io/n8n/security/advisories/GHSA-537j-gqpc-p7fq
ssvc Track https://github.com/n8n-io/n8n/security/advisories/GHSA-537j-gqpc-p7fq
cvssv3.1 8.2 https://nvd.nist.gov/vuln/detail/CVE-2026-42235
cvssv4 8.8 https://nvd.nist.gov/vuln/detail/CVE-2026-42235
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2026-42235
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2026-42235
https://github.com/n8n-io/n8n
https://github.com/n8n-io/n8n/security/advisories/GHSA-537j-gqpc-p7fq
https://nvd.nist.gov/vuln/detail/CVE-2026-42235
GHSA-537j-gqpc-p7fq https://github.com/advisories/GHSA-537j-gqpc-p7fq
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:L Found at https://github.com/n8n-io/n8n
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
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 Found at https://github.com/n8n-io/n8n
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:L Found at https://github.com/n8n-io/n8n/security/advisories/GHSA-537j-gqpc-p7fq
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
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 Found at https://github.com/n8n-io/n8n/security/advisories/GHSA-537j-gqpc-p7fq
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:T/P:M/B:A/M:M/D:T/2026-05-05T14:39:57Z/ Found at https://github.com/n8n-io/n8n/security/advisories/GHSA-537j-gqpc-p7fq
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:L Found at https://nvd.nist.gov/vuln/detail/CVE-2026-42235
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
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 Found at https://nvd.nist.gov/vuln/detail/CVE-2026-42235
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.29849
EPSS Score 0.00115
Published At June 5, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-04T16:51:48.368396+00:00 GithubOSV Importer Import https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-537j-gqpc-p7fq/GHSA-537j-gqpc-p7fq.json 38.6.0