CVE-2026-58661 in n8n
Summary
by MITRE • 07/10/2026
n8n before 2.28.0 (and before 1.123.58 on the 1.x branch) contains a disk space exhaustion vulnerability in the data-table file upload endpoint. The per-request quota check does not account for files already written to the shared temporary directory, allowing an authenticated user to repeatedly upload files that accumulate on disk until the periodic cleanup runs, potentially exhausting available disk space on the host.
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Analysis
by VulDB Data Team • 07/10/2026
This vulnerability affects n8n versions prior to 2.28.0 and 1.123.58 on the 1.x branch, presenting a critical disk space exhaustion threat through its data-table file upload endpoint. The flaw stems from an insufficient per-request quota validation mechanism that fails to consider files already present in the shared temporary directory. An authenticated attacker can exploit this by repeatedly uploading files that accumulate on the system's disk until the periodic cleanup process executes, potentially leading to complete system disk exhaustion and service disruption.
The technical implementation of this vulnerability demonstrates a classic resource exhaustion flaw where the system maintains an incomplete accounting of disk usage during file upload operations. The data-table endpoint accepts file uploads without properly tracking the cumulative disk space consumed by files already stored in the temporary directory, creating a scenario where multiple concurrent or sequential uploads can rapidly deplete available storage capacity. This design flaw allows attackers to consume disk space incrementally through repeated upload operations, bypassing normal quota enforcement mechanisms that only consider the current upload request rather than the total accumulated files.
The operational impact of this vulnerability extends beyond simple denial of service, as it can compromise system stability and availability across multiple n8n instances. When disk space becomes exhausted, the application may become unresponsive or crash entirely, affecting automated workflows and integration processes that depend on n8n's functionality. The vulnerability is particularly concerning in production environments where disk monitoring may be insufficient to detect gradual consumption patterns that could occur over time.
This vulnerability aligns with CWE-400, which addresses excessive resource consumption, and represents a specific implementation of uncontrolled resource consumption in file handling operations. From an attack framework perspective, this weakness maps to the privilege escalation and denial of service categories within the ATT&CK matrix, as authenticated users can leverage their access rights to consume system resources beyond normal operational limits.
Mitigation strategies should include immediate upgrade to n8n versions 2.28.0 or 1.123.58 and higher where this vulnerability has been addressed through proper quota enforcement mechanisms. System administrators should implement additional monitoring for disk space usage patterns and establish automated alerts when storage thresholds approach critical levels. The fix requires modification of the file upload endpoint to maintain accurate accounting of all files in the shared temporary directory, ensuring that per-request quota checks consider the complete disk consumption rather than just the current upload size. Additional defensive measures include implementing stricter limits on concurrent uploads and establishing more frequent cleanup schedules for temporary directories to prevent accumulation of stale files.