CVE-2026-42235

criticalpriority · track · 38EPSS 0.005 · 42 %ileDEEURUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.51% (42nd) EPSS
CVSS 9.6 · critical
Is it mine?
24 products
Check your exposure
Who says so?
6 sources
cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-24

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

9.6
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 5.8–9.6

v3.19.6criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.8 · impact 6
v3.19.6criticalAV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU
v3.18.2highCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:Lsecondary · OSV
v4.08.8highCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:L/SC:H/SI:H/SA:Lsecondary · ENISA EU
v4.08.8highCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/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:Xsecondary · security-advisories@github.com
v4.05.8mediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/E:U/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:Xsecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-79USCWE-79USCWE-79USCWE-87USCWE-87USCWE-87US
04

affected products (24)

Products and version ranges known to be affected.

showing 20 of 24
05

advisories (2)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-1251n8n: Mehrere SchwachstellenDeutsch2026-04-22csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in n8n ausnutzen, um beliebigen Programmcode auszuführen, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, SQL-Injection-Angriffe durchzuführen, einen Denial-of-Service-Zustand verursachen, Cross-Site-Scripting-Angriffe durchzuführen, Benutzer auf bösartige Websites umzuleiten oder Sitzungen zu kapern.

  • GHSA-537j-gqpc-p7fqn8n Vulnerable to XSS via MCP OAuth client2026-04-29ghsa · osvUS

    ## 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.

06

also known as (4)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducert_bundnvdosvNVDCVE.orgMITRE
published 2026-05-04modified 2026-06-17
08

references (4)

External citations — patches, advisories, analysis.

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