CVE-2026-58661: n8n: Authenticated Users Can Exhaust Temporary Disk Storage via Data-Table File Uploads

The data-table file upload endpoint enforces a quota on each request. The check does not count files that earlier uploads already wrote to the shared temporary directory (CWE-770, allocation of resources without limits). An authenticated user can therefore send upload after upload, and each one passes. Temporary files pile up on disk until the periodic cleanup job removes them.

The attacker needs a low-privileged account. No user interaction is needed. The CVSS 4.0 vector lists low availability impact and nothing for confidentiality or integrity.

If uploads outpace cleanup, the host can run out of disk space. A full disk can stop n8n from saving executions and can break other services on the same machine, such as a database sharing the volume. Nothing in the advisory suggests data theft or code execution. The risk is a nuisance outage by any member of a shared instance.

Affected: n8n below 1.123.58 on the 1.x line, and 2.0.0 up to but not including 2.28.0. Instances with users who are not fully trusted, and where the temporary directory shares a volume with other services, carry the most risk.

Check the version:

npm ls n8n

For Docker, check the image tag or the version in the UI.

Upgrade to n8n 1.123.58 or 2.28.0, or later. For an npm install, run npm install [email protected]. The advisory text says to upgrade "once available", but the data lists these two releases as patched.

Temporary mitigations from the advisory, none of which fully remove the risk:

• Restrict instance access to fully trusted users.
• Set uploadMaxFileSize to a low value to limit the size of each upload.
• Monitor and alert on disk usage in the n8n temporary upload directory.

Watch disk usage on the host, in particular the n8n temporary upload directory, for rapid growth. Count the files in that directory and check their timestamps. Many files created close together point to repeated uploads. Check reverse-proxy or access logs for a high rate of requests to the data-table upload endpoint from one authenticated user. Alert on low free space on the volume.

Impact

An authenticated user can repeatedly upload files to the data-table upload endpoint, bypassing the per-request quota check, which does not account for files already written to the shared temporary directory. This causes temporary files to accumulate on disk until the periodic cleanup runs, potentially exhausting available disk space on the host.

Patches

Users should upgrade to the patched version once available to remediate the vulnerability.

Workarounds

If upgrading is not immediately possible, administrators should consider the following temporary mitigations:

• Restrict n8n instance access to fully trusted users only.
• Set uploadMaxFileSize to a low value to limit individual upload size.
• Monitor and alert on disk usage in the n8n temporary upload directory.

These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.