n8n: Anonymous Approval-Gate Bypass via Reused resumeToken over the Chat WebSocket
MediumCVE-2026-86077 · Published Sep 10, 2026
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| n8n npm | >= 2.38.0, < 2.38.2 | 2.38.2 |
| < 2.37.7 | 2.37.7 |
Details and references
## Impact The `/chat` WebSocket route resumed a paused execution from a resume token without checking that the node being resumed was a chat node. n8n hands that token to anonymous form submitters, so a party with no account could present it on the chat route and release an execution waiting at an approval gate, the control an author puts in front of an action considered too consequential to automate. The patch restricts resume over the chat route and Chat Hub to chat-capable node types. ## Patches The issue has been fixed in n8n versions 2.37.7 and 2.38.2. Users should upgrade to one of these versions or later to remediate the vulnerability. ## Workarounds If upgrading is not immediately possible, administrators should consider the following temporary mitigations: - Restrict n8n instance access to fully trusted users only. - Avoid workflows that combine a Form Trigger with non-chat approval gates (Send-and-Wait, Telegram/Slack/Gmail HITL, or plain Wait nodes) on publicly accessible instances. - Audit recent executions of such workflows for unexpected completion without a corresponding approval callback. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.
- CVSS 4.0
- CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- Severity from
- GitHub (reviewed advisory)
- Weakness
- CWE-862
- Also known as
- CVE-2026-86077