Maximum-severity n8n flaw lets randos run your automation server
(2026/01/08)
- Reference: 1767872415
- News link: https://www.theregister.co.uk/2026/01/08/n8n_rce_bug/
- Source link:
A maximum-severity bug in the popular automation platform n8n has left an estimated 100,000 servers wide open to complete takeover, courtesy of a flaw so bad it doesn't even require logging in.
The vulnerability, [1]uncovered by researchers at security outfit Cyera , carries a CVSS score of 10.0 and has been dubbed "ni8mare" for good reason. Tracked as CVE-2026-21858, the flaw allows an unauthenticated attacker to execute arbitrary code on vulnerable systems, effectively handing over complete control of the affected environment. There is no workaround other than patching, and users are urged to upgrade to n8n version 1.121.0 or later.
n8n is a self-hosted, open source automation tool that many organizations use to stitch together chat apps, forms, cloud storage, databases, and third-party APIs. It claims more than 100 million Docker pulls, with millions of users and thousands of companies using it to automate everything from internal workflows to customer-facing processes.
[2]
According to Cyera, the root of the problem lies in how n8n processes webhooks – the mechanism used to kick off workflows when data arrives from external systems such as web forms, messaging platforms, or notification services. By abusing a so-called "Content-Type Confusion" issue, an attacker can manipulate HTTP headers to overwrite internal variables used by the application. That, in turn, allows them to read arbitrary files from the underlying system and escalate the attack to full remote code execution.
[3]
[4]
In plain terms, anyone who can reach a vulnerable n8n instance over the network can seize it completely, without credentials, and then pivot into whatever systems that instance is connected to.
As Cyera researcher Dor Attias put it: "Imagine a large enterprise with 10,000+ employees with one n8n server that anyone uses. A compromised n8n instance doesn't just mean losing one system – it means handing attackers the keys to everything. API credentials, OAuth tokens, database connections, cloud storage – all centralized in one place."
[5]Logitech macOS mouse mayhem traced to expired dev certificate
[6]Cloudflare pours cold water on 'BGP weirdness preceded US attack on Venezuela' theory
[7]IBM's AI agent Bob easily duped to run malware, researchers show
[8]ESA calls cops as crims lift off 500 GB of files, say security black hole still open
That centralization is what makes the flaw so dangerous. n8n is often trusted with high-value secrets and broad access because it orchestrates workflows across an organization's digital estate.
"The blast radius of a compromised n8n is massive," Attias warned. "n8n is connecting countless systems, your organizational Google Drive, OpenAI API keys, Salesforce data, IAM systems, payment processors, customer databases, CI/CD pipelines, and more. It's the central nervous system of your automation infrastructure."
[9]
Cyera credits n8n with responding quickly once the issue was disclosed. The company says it privately reported the vulnerability on November 9, 2025, and n8n's security team confirmed the issue the following day. A fix was quietly shipped on November 18 as part of the 1.121.0 release, weeks before the bug was publicly assigned a CVE identifier this week.
n8n did not immediately respond to The Register 's questions.
The patch landed with little fanfare, which means some organizations may still be running vulnerable versions – particularly in self-hosted environments where upstream advisories don't always get read. Given how widely the software is used, leaving it unpatched is an open invitation for attackers pursuing quick, high-value targets. ®
Get our [10]Tech Resources
[1] https://www.cyera.com/research-labs/ni8mare-unauthenticated-remote-code-execution-in-n8n-cve-2026-21858
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_security/patches&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aV_ivay3IhlD6cYrxJ6p8wAAAtY&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_security/patches&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aV_ivay3IhlD6cYrxJ6p8wAAAtY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_security/patches&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aV_ivay3IhlD6cYrxJ6p8wAAAtY&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[5] https://www.theregister.com/2026/01/08/logitech_mouse_chaos/
[6] https://www.theregister.com/2026/01/08/cloudflare_venezuela_bgp_attack_theory/
[7] https://www.theregister.com/2026/01/07/ibm_bob_vulnerability/
[8] https://www.theregister.com/2026/01/07/european_space_agency_breach_criminal_probe/
[9] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_security/patches&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aV_ivay3IhlD6cYrxJ6p8wAAAtY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[10] https://whitepapers.theregister.com/
The vulnerability, [1]uncovered by researchers at security outfit Cyera , carries a CVSS score of 10.0 and has been dubbed "ni8mare" for good reason. Tracked as CVE-2026-21858, the flaw allows an unauthenticated attacker to execute arbitrary code on vulnerable systems, effectively handing over complete control of the affected environment. There is no workaround other than patching, and users are urged to upgrade to n8n version 1.121.0 or later.
n8n is a self-hosted, open source automation tool that many organizations use to stitch together chat apps, forms, cloud storage, databases, and third-party APIs. It claims more than 100 million Docker pulls, with millions of users and thousands of companies using it to automate everything from internal workflows to customer-facing processes.
[2]
According to Cyera, the root of the problem lies in how n8n processes webhooks – the mechanism used to kick off workflows when data arrives from external systems such as web forms, messaging platforms, or notification services. By abusing a so-called "Content-Type Confusion" issue, an attacker can manipulate HTTP headers to overwrite internal variables used by the application. That, in turn, allows them to read arbitrary files from the underlying system and escalate the attack to full remote code execution.
[3]
[4]
In plain terms, anyone who can reach a vulnerable n8n instance over the network can seize it completely, without credentials, and then pivot into whatever systems that instance is connected to.
As Cyera researcher Dor Attias put it: "Imagine a large enterprise with 10,000+ employees with one n8n server that anyone uses. A compromised n8n instance doesn't just mean losing one system – it means handing attackers the keys to everything. API credentials, OAuth tokens, database connections, cloud storage – all centralized in one place."
[5]Logitech macOS mouse mayhem traced to expired dev certificate
[6]Cloudflare pours cold water on 'BGP weirdness preceded US attack on Venezuela' theory
[7]IBM's AI agent Bob easily duped to run malware, researchers show
[8]ESA calls cops as crims lift off 500 GB of files, say security black hole still open
That centralization is what makes the flaw so dangerous. n8n is often trusted with high-value secrets and broad access because it orchestrates workflows across an organization's digital estate.
"The blast radius of a compromised n8n is massive," Attias warned. "n8n is connecting countless systems, your organizational Google Drive, OpenAI API keys, Salesforce data, IAM systems, payment processors, customer databases, CI/CD pipelines, and more. It's the central nervous system of your automation infrastructure."
[9]
Cyera credits n8n with responding quickly once the issue was disclosed. The company says it privately reported the vulnerability on November 9, 2025, and n8n's security team confirmed the issue the following day. A fix was quietly shipped on November 18 as part of the 1.121.0 release, weeks before the bug was publicly assigned a CVE identifier this week.
n8n did not immediately respond to The Register 's questions.
The patch landed with little fanfare, which means some organizations may still be running vulnerable versions – particularly in self-hosted environments where upstream advisories don't always get read. Given how widely the software is used, leaving it unpatched is an open invitation for attackers pursuing quick, high-value targets. ®
Get our [10]Tech Resources
[1] https://www.cyera.com/research-labs/ni8mare-unauthenticated-remote-code-execution-in-n8n-cve-2026-21858
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_security/patches&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aV_ivay3IhlD6cYrxJ6p8wAAAtY&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_security/patches&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aV_ivay3IhlD6cYrxJ6p8wAAAtY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_security/patches&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aV_ivay3IhlD6cYrxJ6p8wAAAtY&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[5] https://www.theregister.com/2026/01/08/logitech_mouse_chaos/
[6] https://www.theregister.com/2026/01/08/cloudflare_venezuela_bgp_attack_theory/
[7] https://www.theregister.com/2026/01/07/ibm_bob_vulnerability/
[8] https://www.theregister.com/2026/01/07/european_space_agency_breach_criminal_probe/
[9] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_security/patches&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aV_ivay3IhlD6cYrxJ6p8wAAAtY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[10] https://whitepapers.theregister.com/
Re: Good lord...
Anonymous Coward
imo n8n transparently describes itself to be vulnerability-as-a-service so the announcement seems on-brand.
Re: Good lord...
Doctor Syntax
The more you dig into it...
Npm, Javascript, DevOps, Low-code/No-code building. No, nothing to go wrong there.
They have what's termed a SOC 3 report on security. AIUI what this says is that N8N makes assertions about what it does and the auditor confirms that N8N makes its assertions. There seems to be no audit on the product, just an audit on the paperwork.
popular automation platform
Anonymous Coward
Never heard of it
Not a flaw
Anonymous Coward
> lets randos run your automation server
But an opportunity to streamline the headcount.
Am I doing something wrong?
m4r35n357
I run a home "server", which is accessed by various client machines using key-based SSH.
That "server" does NOT have any access to the clients; do I need to fix it?
Re: Am I doing something wrong?
Anonymous Coward
> do I need to fix it?
It can be improved.
I run mine on a Linux 1.6 kernel over telnet with a passwordless root account. Hackers assume it's a honeypot and stay away from it.
Good lord...
"Let's authenticate this one product running LLMs and accepting user input/commands to every single software product in our environment with highly privileged permissions!"
Am i the only one seeing the issue here?