CVE-2026-118679: n8n before 1.123.83, 2.41.4, and 2.42.1 Slack Token Exfiltration via Slack Trigger
n8n before 1.123.83, 2.41.4, and 2.42.1 contains a server-side request forgery vulnerability in the Slack Trigger webhook that allows unauthenticated attackers to exfiltrate Slack tokens by bypassing signature verification when no signing secret is set. Attackers who know the webhook URL can name a file to download, causing the node to send the workspace access token to an attacker host and return the response.
Affected Software
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Deployments using the Slack Trigger webhook without a signing secret are exposed if they run a version before 1.123.83, 2.41.4, or 2.42.1. An attacker must also know the webhook URL.
Does exploitation require credentials or user interaction?
No. The issue is unauthenticated and requires no user interaction, but exploitation has high attack complexity because the attacker needs the webhook URL and the Slack Trigger must have no signing secret configured.
What should be prioritized if an immediate upgrade is not possible?
Configure a signing secret for affected Slack Trigger webhooks, since the signature-verification bypass applies when no signing secret is set. Restrict disclosure and access to webhook URLs as an additional precaution.
What is the impact of successful exploitation?
An attacker can cause the Slack Trigger node to send the workspace access token to an attacker-controlled host by naming a file to download. The node returns the response to the attacker.