Summary
- CVE-2026-21877 is a vulnerability that affects n8n versions 1.65.0 and earlier, allowing attackers to execute code remotely
- The vulnerability uses n8n’s expression engine to gain full system control through authenticated access
- If the vulnerability is successfully exploited, attackers can access credentials, pivot through connected services, and establish persistent access
- Organizations that use n8n should immediately upgrade to version 1.121.0+ to mitigate this critical vulnerability
- SecureLayer7, a leading cybersecurity firm, has published a detailed technical analysis of this exploit, including real-world attack patterns
A critical remote code execution vulnerability has been found in the popular n8n workflow automation platform. This vulnerability puts thousands of businesses at risk of a complete system compromise. This vulnerability, known as CVE-2026-21877, allows authenticated attackers to execute malicious code with the full privileges of the n8n service.
Multiple security agencies have verified the severity of this problem, and exploitation has already been observed in the wild. If left unpatched, organizations using n8n for workflow automation, especially those connecting to sensitive data sources or critical business systems, are at significant risk.
Business Systems in Danger Due to Critical N8N Vulnerability
The n8n workflow automation platform is a favorite among businesses looking to simplify operations through no-code automation. This open-source tool lets organizations link multiple services and automate intricate workflows without the need for deep programming knowledge. However, the discovery of CVE-2026-21877 is a significant threat to organizations that depend on this technology. Considering n8n’s broad permissions to interact with other business systems, successful exploitation could result in widespread compromise that extends well beyond the n8n instance itself.
Both SonicWall’s Capture Labs and SecureLayer7 research teams have independently confirmed that this vulnerability affects both self-hosted deployments and cloud environments. This vulnerability is considered critical because n8n is designed as an integration platform, which means it often connects to databases, cloud storage, customer relationship management systems, and other sensitive business infrastructure. If an attacker were to exploit this vulnerability, they could potentially gain access to all connected systems using the stored credentials and API keys within n8n workflows.
How Bad Is CVE-2026-21858?
This vulnerability is as bad as it gets. It’s been given the highest severity rating because it can give an attacker the ability to execute code with the same privileges as the n8n service, which usually has high-level system access. The fallout from this vulnerability could be more than just data theft. It could also lead to business disruption, ransomware attacks, and ongoing unauthorized access to connected systems. And if your organization is in a regulated industry and sensitive data is exposed through this vulnerability, you could also have compliance issues to deal with.
Versions Impacted (1.65.0 and Prior)
This remote code execution attack affects all n8n installations that are running version 1.65.0 or any previous version. The expression evaluation engine, which processes user-defined workflow logic, is specifically impacted by this vulnerability. The n8n development team has released patched versions (1.120.4, 1.121.1, and 1.122.0), but many organizations are still at risk because of slow update processes. Self-hosted installations are especially at risk because system administrators need to manually update them.
How Hackers Take Advantage of This Weakness
The attack starts when a hacker gains authenticated access to an n8n instance. This can be done by stealing credentials, brute force attacks, or by exploiting weak authentication configurations. Once authenticated, the hacker can create or modify workflows to include malicious JavaScript expressions that break out of n8n’s sandboxed environment. Through specially crafted payloads that target the expression evaluation engine, the hacker can inject code that executes on the underlying operating system. This attack vector is particularly dangerous because n8n’s legitimate functionality requires evaluating user-supplied expressions, making it hard to tell the difference between normal operations and malicious activity.
The Mechanism of the N8N Remote Code Execution Vulnerability
Essentially, this vulnerability takes advantage of a basic security oversight in the way n8n processes JavaScript expressions provided by users. The workflow engine of the platform evaluates these expressions to carry out business logic. However, due to inadequate input validation and sandbox limitations, attackers are able to escape the intended execution context. Attackers can utilize the dynamic execution capabilities of JavaScript to access Node.js system modules and run any commands they wish on the host system.
The Way Attackers Exploit the Vulnerability
The vulnerability lies in n8n’s expression parser, which usually evaluates JavaScript-like expressions for workflow logic. An attacker can create malicious expressions that get around the intended sandbox by accessing Node.js internal modules. The exploit usually involves manipulating the Function constructor or process object to execute arbitrary commands. These payloads can be inserted into workflow node configurations where expressions are evaluated, especially in Function nodes or Code nodes where JavaScript execution is expected.
From a technical standpoint, it is evident that hackers are primarily focusing their attacks on the $env object and a number of JavaScript prototype methods in order to circumvent security measures. By stringing together a series of JavaScript language features, these hackers can gradually elevate their access from simple expression evaluation to complete command execution. This approach has been seen in actual attacks where the threat actors set up reverse shells to keep their access to the systems they’ve compromised.
From Opening Files to Complete System Control
Attacks usually follow a certain pattern, beginning with the ability to access files. Attackers first confirm their code execution by reading sensitive system files like /etc/passwd on Linux systems or system configuration files on Windows. After confirming file access, attackers move on to executing system commands, often using web shells or setting up reverse connections to command and control servers. The last step is to harvest credentials from n8n’s stored connections and move laterally to other systems that can be accessed with those credentials.
This vulnerability is particularly dangerous because attackers can automate the entire chain of exploitation. Publicly available proof-of-concept exploits demonstrate how attackers can go from initial access to persistent system control in under a minute, leaving minimal traces in standard logging systems. Since the code execution happens within legitimate n8n processes, traditional detection systems may fail to identify the malicious activity.
The Appeal of Workflow Automation Tools for Attackers
Workflow automation platforms such as n8n are often the prime targets for attackers because they provide privileged access to multiple systems and stored credentials. These platforms usually have connections with databases, cloud services, email systems, and other critical business infrastructures. By compromising a workflow automation platform, attackers can access several systems from a centralized point without having to individually breach each system. The potential for credential harvesting alone makes these platforms a high-value target in complex attack campaigns.
Moreover, workflow automation tools usually run with high-level privileges to carry out their tasks. If these tools are compromised, hackers can take over these privileges, often getting administrator-level access to the system. This privileged position allows for persistent access, data extraction, and the deployment of more harmful tools with a low risk of detection.
What to Do Right Now to Secure Your N8N System
If you’re using n8n, consider this vulnerability a serious security breach that needs immediate action. The best way to protect your system is to upgrade to the latest patched version (1.121.0 or later) as soon as you can. This update has full fixes for the expression evaluation engine to stop remote code execution attempts. Because this vulnerability is so serious and there’s evidence it’s being actively exploited, you should put emergency patching procedures in place, even if it means temporarily disrupting your normal business operations.
For companies with complex deployment situations, the n8n development team has released detailed upgrade instructions specific to different installation methods. Docker users need to pull the latest image and rebuild their containers, while npm installations need specific upgrade commands with clean cache procedures. The development team also suggests doing a workflow backup before upgrading to avoid any potential data loss during the update process. Additionally, they are exploring revolutionary AI enhancements to further streamline their processes.
Upgrade to Version 1.121.0+ Now
The n8n development team has fixed this vulnerability in version 1.121.0 and later versions. The security patch correctly sandboxes the expression evaluation engine and limits access to dangerous JavaScript functions like the Function constructor and Node.js system modules. More validation checks have been added to stop prototype pollution attacks and escape attempts from the intended execution context. The updated version also includes better logging for security-related events to help identify potential exploitation attempts.
It’s important to follow the given installation instructions closely when you’re upgrading. If you don’t, you might leave behind vulnerable components or configuration files that could still be taken advantage of. After you upgrade, you can check to make sure the installation was successful by looking at the version number. You can find this in the n8n interface under Settings > About. Companies should also do security testing on the upgraded installation to make sure the vulnerability has been taken care of properly.
What to Do If You Can’t Upgrade Right Away
If you can’t upgrade right away, there are some temporary fixes that can help lower the risk. The best temporary fix is to limit network access to the n8n interface. You can do this with network segregation, VPNs, or IP-based access controls. Using strong multi-factor authentication methods can also help keep unauthorized users out. Finally, keep a close eye on n8n processes and network traffic to catch any attempts to exploit the system.
Companies that must keep vulnerable versions temporarily should consider deploying the platform in a containerized environment with limited privileges to mitigate the potential impact of exploitation. Another way to limit the attack surface is by removing unnecessary workflow connections, especially those with high privileges or access to sensitive systems. However, these are only short-term solutions while you prepare for an appropriate upgrade.
How Hackers Use This Vulnerability to Attack
Knowing how an attack works can help organizations spot possible signs of compromise in their systems. The way CVE-2026-21877 is usually exploited is fairly predictable and something security teams should keep an eye out for. Attackers start by getting authentication for the n8n platform. They then make or change workflows that contain harmful expressions. Finally, they run these workflows to get access to the system.
How Attackers Gain Access
Attackers first need to get authenticated access to the n8n platform. This is typically done by using stolen credentials or by exploiting instances with weak authentication settings. Once they are authenticated, they look for or create workflows that use the Function node or Code node components, which allow them to execute custom JavaScript. They can then embed malicious code within these components, which will trigger the vulnerability when the workflow is executed. If you look at the security logs, you’ll often see that there was legitimate authentication, followed by suspicious workflow creation or modification activity, right before the exploitation. For more insights on technology partnerships, check out Park Place Technologies’ recent collaboration.
Techniques for Escalating Privileges
Once attackers have gained initial code execution, they use various techniques to increase their privileges within the target environment. They often access environment variables to extract sensitive configuration data, read credential files stored on the filesystem, and exploit service accounts that are not properly configured. The n8n service usually runs with enough privileges to access system resources, which attackers use to increase their control. In containerized deployments, attackers might try container escape techniques to gain access to the host system.
After gaining higher-level privileges, attackers usually establish long-term access methods like backdoor accounts, timed tasks, or harmful service installations. These persistence methods ensure ongoing access, even if the initial vulnerability gets fixed.
Risks of Data Exposure
The vulnerability’s most significant risk is the exposure of sensitive data. Attackers can access credentials stored in n8n workflows, including API keys, database connection strings, and authentication tokens for connected services. These credentials often have extensive permissions across the organization’s technology stack. Furthermore, attackers can directly access data processed by n8n workflows, potentially exposing customer information, financial data, or proprietary business intelligence.
Worries about Network Spreading
When attackers have infiltrated an n8n instance, they usually move on to other systems using the credentials they’ve obtained. The interconnectedness of workflow automation platforms makes them perfect for moving laterally across networks. Attackers can take advantage of the trusted connections between systems to get around perimeter security controls and gain access to more resources. Security teams should be on the lookout for strange connection patterns from n8n servers, especially connections to systems or services that aren’t part of the established workflows.
Wider Security Consequences for Business Automation
The n8n vulnerability underscores wider security issues with low-code/no-code automation platforms that have become increasingly popular in business settings. These platforms often operate with elevated privileges and access to multiple systems, making them high-value targets for attackers. Organizations should reassess their security posture around all automation tools, not just n8n, as similar vulnerabilities could exist in related products.
Comparable Security Risks in Similar Tools
This security risk is not unique to n8n, and is a common problem in workflow automation platforms that use expression evaluation engines. Other automation tools that allow users to define their own logic using JavaScript or other scripting languages have had similar issues. The main issue is striking a balance between allowing for flexibility in legitimate business logic and preventing the execution of malicious code. Companies should review all automation platforms they use for similar security considerations, especially those that support custom code or expression evaluation.
The Importance of Strong Security Measures in Automation Platforms
Automation platforms often occupy a privileged position in a company’s technology ecosystem, which is why it’s essential to have strong security measures in place. These tools often connect a variety of systems and manage sensitive data flows that cross organizational lines. If compromised, the impact could be felt not only on the platform but also on all connected systems. Therefore, it’s crucial for companies to use defense-in-depth strategies designed to protect automation platforms. This could include network segregation, managing privileged access, and comprehensive monitoring.
While businesses are turning to automation to increase efficiency, it’s important to remember that security needs to be a part of the conversation. It’s not something that should be tacked on after the fact, but instead, it should be a part of the project from the very beginning.
Long-Term Security Measures for Workflow Automation Tools
In addition to addressing the immediate vulnerability, organizations should put in place robust security measures for all workflow automation platforms. These controls help to reduce the risk of future vulnerabilities while enhancing overall security posture.
Enforce Strong Access Limitations
Access to n8n and other workflow automation platforms needs to be strictly limited to only those who are authorized. Implement role-based access control to make sure users can only access the specific workflows and functions they need for their job responsibilities. Require strong authentication mechanisms, preferably multi-factor authentication, for all users who have access to the platform. Regular access reviews should be conducted to identify and remove unnecessary permissions, particularly for administrative functions that could be leveraged in an attack.
Isolated Environment Deployment
It’s crucial to deploy workflow automation platforms in isolated network segments that have limited communication paths. By using network segmentation, you can restrict the systems and services that n8n instances can interact with. This follows the principle of least privilege. Instead of allowing direct connectivity, consider using jump servers or bastion hosts for administrative access to these platforms. If you’re dealing with critical workflows that handle sensitive data, it might be appropriate to use dedicated instances that have stricter security controls. This could help minimize the potential impact if a compromise occurs.
Consistent Security Checks and Reviews
Regularly carry out vulnerability scanning and penetration testing for all workflow automation platforms. These checks should focus on the expression evaluation features and custom code components where vulnerabilities like CVE-2026-21877 are most likely to be found. Also, perform regular security reviews of workflow configurations to spot potentially harmful patterns or excessive permissions that could be taken advantage of. Custom scripts and functions within workflows should be reviewed for security weaknesses.
Security Best Practices for n8n Deployments
- Authentication: Enable OIDC/SAML integration with corporate identity providers
- Authorization: Implement role-based access with minimal necessary permissions
- Network: Deploy behind VPN or zero-trust network access solutions
- Monitoring: Enable detailed audit logging and SIEM integration
- Updates: Establish automated patch management procedures
These security controls should be documented in organizational security policies and procedures. Regular training for both administrators and users of workflow automation platforms helps ensure security considerations are understood and followed. As with any critical business system, include these platforms in disaster recovery and incident response planning to enable quick reaction to security incidents.
While setting up these safeguards, it’s important to strike a balance between security needs and the needs of the business. If the controls are too tight, users might look for ways around them or find other solutions that could pose even more security risks. By working together, security teams and business stakeholders can make sure security is adequate without getting in the way of productivity.
Keeping an Eye Out for Unusual Behaviour
Set up thorough monitoring and alerting for n8n instances to catch potential exploitation attempts. Pay special attention to workflow creation or modification events, especially those involving Function nodes or Code nodes where harmful code could be added. Set up alerts for strange execution patterns or unexpected system calls from the n8n process. Combine logs with security information and event management (SIEM) systems to correlate with other security events.
Enhanced monitoring should incorporate behavioral analysis to identify unusual workflow execution patterns that could signify a breach. For instance, workflows that suddenly access new systems, handle abnormal data volumes, or operate at unexpected times could be signs of malicious activity. Define what constitutes normal behavior for operations to make unusual activity more noticeable.
Think about using runtime application self-protection (RASP) or similar technologies that can identify and stop potentially harmful activities within the application context. These solutions can provide an extra layer of defense against attempts to exploit, especially for instances that cannot be updated immediately.
Commonly Asked Questions
Companies usually have a number of questions they ask when dealing with this vulnerability. The guidance below addresses the most common concerns raised by security teams and system administrators who are dealing with potentially vulnerable n8n installations.
How can I tell if my n8n instance is at risk?
You can find out if your n8n instance is at risk by looking at the version number that is installed. Go to the Settings > About section in the n8n web interface to see what version you’re currently using. If you’re using version 1.65.0 or an earlier version, then your instance is at risk of this remote code execution attack. Also, take a look at your n8n deployment configuration to see if you’ve put in place any of the recommended mitigation measures, such as network isolation or restricted authentication, that could lower the risk of exploitation.
For companies that have many n8n instances or are using containerized deployments, it’s important to check the version of each instance separately. Some environments may have mixed versions because of staggered update processes or separate deployment pipelines. Automated vulnerability scanning tools that can identify this specific CVE may also be useful for large-scale deployments.
Is authentication required to exploit this vulnerability?
Under normal circumstances, this vulnerability requires authenticated access to the n8n platform for exploitation. However, security researchers have discovered cases where the authentication requirement could be bypassed in specific deployment configurations. Organizations that use custom authentication integrations or have exposed n8n instances directly to the internet may be at a higher risk of unauthenticated exploitation. Furthermore, some organizations set up public-facing webhooks that trigger workflows, which could potentially be used as part of an attack chain.
This vulnerability is still critical, even though authentication is required. This is because credential theft is a common attack vector. Attackers may gain the necessary credentials to access n8n instances through phishing attacks, password spraying, or the exploitation of related systems. Organizations should not view the requirement for authentication as enough protection against this vulnerability.
Does this affect cloud-hosted n8n instances as well?
Indeed, both self-hosted and cloud-hosted n8n instances are vulnerable to this security issue if they’re operating on vulnerable versions. The official n8n Cloud service has been patched, but customer-managed cloud deployments on platforms such as AWS, Azure, or Google Cloud necessitate manual updates by the organization’s administrators. Cloud deployments may actually be at a greater risk due to their public accessibility if proper security measures aren’t in place. Organizations that use cloud-hosted instances should check their version and update immediately if they’re running vulnerable versions.
When you’re updating your instances in the cloud, make sure to adhere to the procedures for updates that are specific to your provider. This is to ensure that your service continues without interruption. There might be some extra steps you need to take with some models for cloud deployment compared to installations that are on-premises. Once you’ve updated, check to make sure that your workflows are still functioning as they should be and that none of your configuration changes were lost during the process of updating.
What data could be compromised if this vulnerability is exploited?
If this vulnerability is exploited, any data that the n8n platform can access or process could potentially be compromised. This includes credentials stored within n8n for connecting to other systems, data processed within workflows, and potentially any information accessible to the operating system user that runs the n8n service. Because n8n is so extensible, it often has access to databases, CRM systems, email platforms, cloud storage, and other business-critical systems, which significantly expands the potential impact of a compromise.
How soon do I need to apply the security patch?
This vulnerability is a critical issue that needs to be patched immediately. There is evidence of active exploitation in the wild, meaning attackers are already targeting systems that are vulnerable. If necessary, organizations should implement emergency change procedures to apply updates outside of normal maintenance windows. The risk of exploitation and the potential for system compromise far outweighs the potential disruption from an emergency update process.
If you can’t patch your critical business systems right away, use the recommended mitigation measures in the meantime. Make sure to keep track of any temporary security controls you put in place so you can review them after you patch your systems and decide whether to keep them as additional security measures.
Keep in mind that simply applying patches might not be enough if systems have already been breached. After you’ve updated, carry out comprehensive security evaluations to look for signs of compromise that might indicate past exploitation. Check workflow settings for unauthorized alterations and inspect system logs for anything out of the ordinary.
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