CVE-2026-56358Network attack vector

Form hijacking via faulty CSS sanitization

Published Jun 24, 2026 · Updated Jun 24, 2026

Stored XSS in n8n 1.x before 1.123.25 and 2.x before 2.11.2 allows remote authenticated users to hijack published forms. The Form Trigger node's CSS sanitizer fails to neutralize malicious input, causing stored payloads to run in every form visitor's browser. Exploitation requires workflow creation or editing permission and a form visitor; CSP blocks direct session-cookie theft but not script execution, action changes, or phishing.

CVSS severity5.1
Medium
EPSS probability0.24%
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 1.x before 1.123.25 and 2.x before 2.11.2 allows remote authenticated users to hijack published forms. The Form Trigger node's CSS sanitizer fails to neutralize malicious input, causing stored payloads to run in every form visitor's browser. Exploitation requires workflow creation or editing permission and a form visitor; CSP blocks direct session-cookie theft but not script execution, action changes, or phishing.

The record

CVE
CVE-2026-56358
Published
Jun 24, 2026
Updated
Jun 24, 2026
Vendor
n8n
Product
n8n
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 24, 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=0 <1.123.25
  2. Affected versionversion=0 <2.11.2
  3. Affected versionversion=2.0.0-rc.0 <2.11.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

n8n · n8nversion=0 <1.123.25; version=0 <2.11.2; version=2.0.0-rc.0 <2.11.2

Published CVSS scores

5.4VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
T1203Exploitation for Client Execution

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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