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RCE via Arbitrary File Write in n8n
A critical authenticated remote code execution vulnerability in n8n allows an authenticated attacker to cause untrusted code to be executed by the n8n service, potentially resulting in full compromise of the affected instance. The issue has been described as an arbitrary file write condition and also as an unrestricted upload of a file with a dangerous type, indicating insufficient validation of attacker-controlled input that can lead to writing executable or otherwise dangerous content in a location later processed by the service. The vulnerability affects both self-hosted deployments and n8n Cloud. Reported affected versions are n8n 0.123.0 through versions prior to 1.121.3.
What it means and what to do now: patch path, interim mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
Successful exploitation can lead to authenticated remote code execution in the context of the n8n service and full takeover of the affected instance. Because n8n commonly operates as an automation hub with access to workflows, integrations, credentials, and connected internal systems, compromise can expose sensitive data, stored secrets, and downstream systems reachable through the platform. Impact may include arbitrary command execution, workflow tampering, credential theft, lateral movement, and persistent control of the automation environment.
If you can’t patch tonight, do this now.
If immediate patching is not possible, reduce exposure by disabling the Git node and restricting access for untrusted users. Limit workflow creation and modification privileges to trusted administrators only. Additional risk reduction can be achieved by minimizing authenticated access to n8n, especially for lower-trust users, until the patched version is deployed.
Patch, then assume compromise.
Upgrade n8n to version 1.121.3 or later. This version contains the vendor fix for CVE-2026-21877. Organizations should prioritize patching across both self-hosted and cloud-managed deployments and verify that all instances are running a non-vulnerable release.
2 exploits validated by Mallory's analysis. Hidden: 1 rejected by Mallory's analysis as not a working exploit.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
69 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.