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Fencer Intel
high 7.5

CVE-2026-126391 json

n8n before 1.123.89 RCE via Workflow Expression Evaluation Sandbox Escape

published 18d ago modified yesterday also EUVD-2026-125174 , GHSA-gx3v-3x3v-f8r5

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository n8n-io/n8n. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

Summary

n8n before 1.123.89 contains an insufficient isolation vulnerability in workflow expression evaluation that allows authenticated users to escape the sandbox. Attackers with permission to create or modify workflows can craft expressions referencing unexpected JavaScript properties to execute arbitrary code on the n8n host.

Patch / fix

  • npm n8n >= 1.123.89, >= 2.45.5, >= 2.46.1, >= 3.0.1
  • n8n-io n8n 1.123.89, 2.45.5, 2.46.1, 3.0.1

Is CVE-2026-126391 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.

Check with Fencer

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
yesterday

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-14).

CVSS scores

assigned by version score vector
CNA 4.0 7.7 CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 4.0 7.7 CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/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

Affected packages

ecosystem package affected fixed in
npm n8n
<1.123.89
<2.46.1
<2.45.5
<3.0.1
>= 1.123.89
>= 2.46.1
>= 2.45.5
>= 3.0.1

Affected products

  • n8n-io n8n

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

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.

The maintainers of n8n-io/n8n published their own advisory on GitHub. Reviewed sources take precedence over it.