AI agent vulnerability · n8n

CVE-2026-86081: n8n: Regular Expression Denial of Service in the Default Blocked-File-Pattern Match via a Git Node Clone Path

highCVSS 4.0 7.1GHSA-j535-v25q-vx3q

Impact The Git node's clone operation matched the destination path against the default N8NBLOCKFILEPATTERNS expression, which was written so that a crafted path caused catastrophic backtracking. Evaluation runs synchronously in the main n8n process, so an authenticated user could freeze the instance for everyone with a single workflow execution and no unusual configuration.

Published Sep 10, 2026

Affected packages

n8n

Ecosystem: npm
Affected: < 1.123.76
Fixed in: 1.123.76
Check: npm ls n8n

n8n

Ecosystem: npm
Affected: >= 2.38.0, < 2.38.2
Fixed in: 2.38.2
Check: npm ls n8n

n8n

Ecosystem: npm
Affected: >= 2.0.0, < 2.37.7
Fixed in: 2.37.7
Check: npm ls n8n

Advisory details

From the GitHub Advisory Database (CC BY 4.0).

Impact

The Git node's clone operation matched the destination path against the default N8N_BLOCK_FILE_PATTERNS expression, which was written so that a crafted path caused catastrophic backtracking. Evaluation runs synchronously in the main n8n process, so an authenticated user could freeze the instance for everyone with a single workflow execution and no unusual configuration. The patch rewrites the pattern so that matching is linear in the length of the path.

Patches

The issue has been fixed in n8n versions 1.123.76, 2.37.7, and 2.38.2. Users should upgrade to one of these versions or later 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.
Disable the Git node by adding n8n-nodes-base.git to the NODES_EXCLUDE environment variable.
Set N8N_BLOCK_FILE_PATTERNS to a backtracking-safe equivalent pattern to replace the vulnerable default.

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

Credited to Masofgon.

References

How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology

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