PT-2026-88509 · Git+3 · N8N
CVE-2026-86078
·
Published
2026-09-08
·
Updated
2026-09-10
CVSS v4.0
6.0
Medium
| Vector | AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
Impact
The Instance AI workflow summary built its result with get-or-create-then-nested-write idioms keyed by node names and connection keys taken from the stored workflow. Those are arbitrary strings: the restricted-name guard n8n shows in the editor is client-side and is bypassed by posting the workflow to the REST API directly. So a reserved key such as
proto resolved up the prototype chain instead of creating an own key, and the write landed on Object.prototype in the main n8n process, affecting every later request. The patch builds the summary with null-prototype accumulators and validates the keys it accepts, so reserved names cannot reach the prototype chain.Patches
The issue has been fixed in n8n versions 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.
- Remove or leave unconfigured the
N8N INSTANCE AI MODEL*environment variables to prevent the Instance AI module from reaching the vulnerable code path. - Restart the n8n process to clear any in-memory prototype pollution if an attack is suspected.
These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.
Exploit
Fix
Prototype Pollution
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Weakness Enumeration
Related Identifiers
Affected Products
N8N