Allocation of Resources Without Limits or Throttling in n8n - #VU127221
Published: April 23, 2026
Vulnerability identifier: #VU127221
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-770
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: n8n
Affected software:
n8n
n8n
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper resource control in the MCP OAuth client registration endpoint when handling unauthenticated client registration requests. A remote attacker can send large registration payloads to cause a denial of service.
The endpoint is reachable regardless of whether MCP access is enabled on the instance.
Remediation
Install security update from vendor's website.