n8n-io n8n up to 1.123.79/2.39.5/2.40.0 Webhook improper authentication

Summaryinfo

A vulnerability identified as problematic has been detected in n8n-io n8n up to 1.123.79/2.39.5/2.40.0. Affected by this issue is some unknown functionality of the component Webhook Handler. The manipulation leads to improper authentication. This vulnerability is traded as CVE-2026-103245. It is possible to initiate the attack remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in n8n-io n8n up to 1.123.79/2.39.5/2.40.0. This issue affects some unknown functionality of the component Webhook Handler. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is integrity. The summary by CVE is:

n8n versions before 1.123.80, from 2.0.0 before 2.39.6, and from 2.40.0 before 2.40.1 fail to verify the x-webflow-signature HMAC in the Webflow Trigger node webhook handler. Unauthenticated attackers can send forged webhook requests with attacker-controlled payloads to trigger workflows and manipulate downstream actions like record creation or API calls.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-103245 since 09/30/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available.

Upgrading to version 1.123.80, 2.39.6 or 2.40.1 eliminates this vulnerability.

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Productinfo

Vendor

• n8n-io

Name

• n8n

Version

• 1.123.0
• 1.123.1
• 1.123.2
• 1.123.3
• 1.123.4
• 1.123.5
• 1.123.6
• 1.123.7
• 1.123.8
• 1.123.9
• 1.123.10
• 1.123.11
• 1.123.12
• 1.123.13
• 1.123.14
• 1.123.15
• 1.123.16
• 1.123.17
• 1.123.18
• 1.123.19
• 1.123.20
• 1.123.21
• 1.123.22
• 1.123.23
• 1.123.24
• 1.123.25
• 1.123.26
• 1.123.27
• 1.123.28
• 1.123.29
• 1.123.30
• 1.123.31
• 1.123.32
• 1.123.33
• 1.123.34
• 1.123.35
• 1.123.36
• 1.123.37
• 1.123.38
• 1.123.39
• 1.123.40
• 1.123.41
• 1.123.42
• 1.123.43
• 1.123.44
• 1.123.45
• 1.123.46
• 1.123.47
• 1.123.48
• 1.123.49
• 1.123.50
• 1.123.51
• 1.123.52
• 1.123.53
• 1.123.54
• 1.123.55
• 1.123.56
• 1.123.57
• 1.123.58
• 1.123.59
• 1.123.60
• 1.123.61
• 1.123.62
• 1.123.63
• 1.123.64
• 1.123.65
• 1.123.66
• 1.123.67
• 1.123.68
• 1.123.69
• 1.123.70
• 1.123.71
• 1.123.72
• 1.123.73
• 1.123.74
• 1.123.75
• 1.123.76
• 1.123.77
• 1.123.78
• 1.123.79
• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24
• 2.25
• 2.26
• 2.27
• 2.28
• 2.29
• 2.30
• 2.31
• 2.32
• 2.33
• 2.34
• 2.35
• 2.36
• 2.37
• 2.38
• 2.39
• 2.39.0
• 2.39.1
• 2.39.2
• 2.39.3
• 2.39.4
• 2.39.5
• 2.40.0

Website

• Product: https://github.com/n8n-io/n8n/

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