n8n: Regular Expression Denial of Service in the Default Blocked-File-Pattern Match via a Git Node Clone Path
HighCVE-2026-86081 · Published Sep 10, 2026
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| n8n npm | < 1.123.76 | 1.123.76 |
| >= 2.38.0, < 2.38.2 | 2.38.2 | |
| >= 2.0.0, < 2.37.7 | 2.37.7 |
Details and references
## 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.
- CVSS 4.0
- CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Severity from
- GitHub (reviewed advisory)
- Weakness
- CWE-1333
- Also known as
- CVE-2026-86081