GHSA-j535-v25q-vx3q n8n: Regular Expression Denial of Service in the Default Blocked-File-Pattern Match via a Git Node Clone Path

• npm n8n: < 1.123.76 → fixed in 1.123.76 • npm n8n: >= 2.38.0, < 2.38.2 → fixed in 2.38.2 • npm n8n: >= 2.0.0, < 2.37.7 → fixed in 2.37.7

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.