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Fencer Intel
critical 9.0

CVE-2026-33749 json

n8n Vulnerable to XSS via Binary Data Inline HTML Rendering

published 7mo ago modified 4mo ago also EUVD-2026-15956 , GHSA-qfc3-hm4j-7q77

cvss
9.0
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

n8n is an open source workflow automation platform. Prior to versions 1.123.27, 2.13.3, and 2.14.1, an authenticated user with permission to create or modify workflows could craft a workflow that produces an HTML binary data object without a filename. The `/rest/binary-data` endpoint served such responses inline on the n8n origin without `Content-Disposition` or `Content-Security-Policy` headers, allowing the HTML to render in the browser with full same-origin JavaScript access. By sending the resulting URL to a higher-privileged user, an attacker could execute JavaScript in the victim's authenticated session, enabling exfiltration of workflows and credentials, modification of workflows, or privilege escalation to admin. The issue has been fixed in n8n versions 1.123.27, 2.13.3, and 2.14.1. Users should upgrade to one of these versions or later to remediate the vulnerability. If upgrading is not immediately possible, administrators should consider the following temporary mitigations: Limit workflow creation and editing permissions to fully trusted users only, and/or restrict network access to the n8n instance to prevent untrusted users from accessing binary data URLs. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.

Patch / fix

  • npm n8n 1.123.27, 2.13.3, 2.14.1
  • n8n n8n 1.123.27, 2.13.3, 2.14.1

Is CVE-2026-33749 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
7mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:H/SI:H/SA:H
GitHub 3.1 8.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:H/SI:H/SA:H/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
NVD 3.1 9.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm n8n
<1.123.27
>=2.14.0, <2.14.1
>=2.0.0-rc.0, <2.13.3
1.123.27
2.14.1
2.13.3

Affected products

  • n8n-io n8n

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.