Impact
The use of Buffer.allocUnsafe() and Buffer.allocUnsafeSlow() in the task runner allowed untrusted code to allocate uninitialized memory. Such uninitialized buffers could contain residual data from within the same Node.js process (for example, data from prior requests, tasks, secrets, or tokens), resulting in potential information disclosure.
Only authenticated users are able to execute code through Task Runners.
This issue affected any deployment in which both of the following conditions were met:
- Task Runners were enabled using
N8N_RUNNERS_ENABLED=true (default: false)
- Code Node was enabled (default: true)
Patches
Access to unsafe Buffer functions has been removed from the task runner sandbox. All buffer allocations are now zero-filled by default.
- Fixed in: 1.114.3 & 1.115.0
- Action: It is strongly recommended to upgrade to version ≥ 1.114.3 as soon as possible.
Changes introduced in this patch include:
- Routing all buffer allocations through
Buffer.alloc (which zero-fills) operations where applicable
- Adding regression tests to ensure continued enforcement of safe allocation practices
Workarounds
If an immediate upgrade cannot be applied, the following hardening steps are recommended:
- Disable the Code Node by adding
n8n-nodes-base.code to the NODES_EXCLUDE environment variable
- Prefer external mode for isolation: run Task Runners in external mode so that untrusted task code executes in a separate sidecar container rather than within the main n8n process. This configuration significantly reduces the risk of in-process memory disclosure caused by unsafe buffer allocations.
In external mode, a launcher manages Task Runner processes in a dedicated sidecar environment, separate from the primary n8n instance.
See the n8n documentation for configuration details and required environment variables.
Resources
References
Impact
The use of
Buffer.allocUnsafe()andBuffer.allocUnsafeSlow()in the task runner allowed untrusted code to allocate uninitialized memory. Such uninitialized buffers could contain residual data from within the same Node.js process (for example, data from prior requests, tasks, secrets, or tokens), resulting in potential information disclosure.Only authenticated users are able to execute code through Task Runners.
This issue affected any deployment in which both of the following conditions were met:
N8N_RUNNERS_ENABLED=true(default: false)Patches
Access to unsafe Buffer functions has been removed from the task runner sandbox. All buffer allocations are now zero-filled by default.
Changes introduced in this patch include:
Buffer.alloc(which zero-fills) operations where applicableWorkarounds
If an immediate upgrade cannot be applied, the following hardening steps are recommended:
n8n-nodes-base.codeto theNODES_EXCLUDEenvironment variableIn external mode, a launcher manages Task Runner processes in a dedicated sidecar environment, separate from the primary n8n instance.
See the n8n documentation for configuration details and required environment variables.
Resources
Buffer.alloc()vsBuffer.allocUnsafe()— background on zero-filled vs uninitialized allocationsReferences