n8n-io n8n up to 2.39.5/2.40.0 Dynamic Credentials improper authorization

Summaryinfo

A vulnerability was found in n8n-io n8n up to 2.39.5/2.40.0 and classified as critical. Affected is an unknown function of the component Dynamic Credentials. Such manipulation leads to improper authorization. This vulnerability is listed as CVE-2026-103259. The attack may be performed from remote. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in n8n-io n8n up to 2.39.5/2.40.0. Affected by this issue is an unknown code of the component Dynamic Credentials. The manipulation with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality, integrity, and availability. CVE summarizes:

n8n versions before 2.39.6 and 2.40.0 before 2.40.1 contain a session token leakage vulnerability in the Dynamic Credentials authorize and revoke endpoints. Attackers with resolver registration capability can capture collaborators' session tokens by setting a fallback resolver to an attacker-controlled endpoint during the account connection flow, enabling unauthorized credential access.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-103259 since 09/30/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1548.002 by the MITRE ATT&CK project.

Upgrading to version 2.39.6 or 2.40.1 eliminates this vulnerability.

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Productinfo

Vendor

• n8n-io

Name

• n8n

Version

• 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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