CVE-2026-103259: n8n-Io n8n

High severity, CVSS 7.6. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• n8n-Io n8n: before 2.39.6 (fixed in 2.39.6); from 2.40.0, before 2.40.1 (fixed in 2.40.1)

Published 2026-10-01. Last modified 2026-10-01.