CVE-2026-25051Network attack vector

Account takeover via whitespace-bypassed sandbox CSP

Published Feb 4, 2026 · Updated Feb 4, 2026

Stored XSS in n8n before 1.123.2 allows remote authenticated users to run same-origin scripts through crafted webhook responses. The isHtmlRenderedContentType function lowercases but does not trim a response Content-Type, so leading whitespace before text/html avoids the HTML classification that adds the sandbox CSP. Workflow creation or modification rights and another user's interaction are required, exposing the victim's session to hijacking and account takeover.

CVSS severity8.5
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in n8n before 1.123.2 allows remote authenticated users to run same-origin scripts through crafted webhook responses. The isHtmlRenderedContentType function lowercases but does not trim a response Content-Type, so leading whitespace before text/html avoids the HTML classification that adds the sandbox CSP. Workflow creation or modification rights and another user's interaction are required, exposing the victim's session to hijacking and account takeover.

The record

CVE
CVE-2026-25051
Published
Feb 4, 2026
Updated
Feb 4, 2026
Vendor
n8n
Product
n8n
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.123.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

n8n · n8nversion=< 1.123.2

Published CVSS scores

8.5n8nCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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