CVE-2026-77070 is a critical (CVSS 9.8 in NVD) NoSQL injection in the n8n MongoDB node. Find, Delete and Aggregate parse the Query field as JSON after expressions resolve, with no operator sanitizing. Upgrade to n8n 1.123.69, 2.33.4 or 2.34.1, or later, and audit workflows that feed external data into queries.
What's affected
- Product: n8n, the MongoDB node (Find, Delete and Aggregate operations).
- Affected: n8n before 1.123.69, before 2.33.4 and before 2.34.1, on their respective lines.
- Fixed: 1.123.69, 2.33.4 and 2.34.1.
- Weakness: CWE-943, improper neutralization of special elements in data query logic.
- Score: NVD lists CVSS 9.8. The n8n advisory rates it 7.1 on CVSS v4, with high subsequent system impact. Not listed in CISA KEV.
How to check if you're exposed
Check the n8n version.
n8n --version
# or, for Docker
docker exec <container> n8n --version
Then find workflows that use the MongoDB node. Export them and search for the node type.
n8n export:workflow --all --output=workflows.json
grep -c "n8n-nodes-base.mongoDb" workflows.json
For each match, see whether the Query field contains an expression that resolves to data from a webhook, form, email or any other outside source. Those are the workflows the advisory is about.
What to do now
- Upgrade n8n to 1.123.69, 2.33.4 or 2.34.1, or later, matching your release line.
- Audit workflows with the MongoDB node, and remove expressions in the Query field that resolve to outside data.
- Restrict network access to webhook and trigger endpoints that feed MongoDB queries, and require authentication on them.
- If you cannot upgrade, add
n8n-nodes-base.mongoDbto the NODES_EXCLUDE environment variable until you can. - Review MongoDB logs for large or unusual reads and deletes issued by the n8n service account, and give that account only the rights it needs.
Why it matters
The node took a query string, resolved expressions into it, then parsed the result as JSON. Operators that MongoDB uses for comparison and code evaluation were not stripped. A value meant to be one document ID could therefore change the meaning of the whole query.
This is injection in a new setting. Workflow tools make it easy to wire untrusted input into a database call with one expression. Give the database account in a workflow tool the least rights that work.
Try it yourself
Click through it at your own pace, or open it full screen.
Quick check
Who can trigger this?
The record says an attacker who can influence the resolved query is needed, for example through externally controlled data feeding a workflow.
Is disabling the node a full fix?
No. The advisory says workarounds only reduce risk and are short-term. Upgrade.
Sources
Last reviewed: 19 October 2026.
