Medium severity · published Sep 8, 2026
CVE-2026-86078
n8n: Prototype Pollution via Workflow Structure Summary Can Lead to Denial of Service
6.5
CVSS
0.6%
EPSS
No
On KEV
Description
n8n is an open source workflow automation platform. Prior to 2.37.7 and 2.38.2, the Instance AI workflow summary used node names and connection keys from stored workflows as ordinary object keys. A workflow submitted through the REST API could contain __proto__ or constructor, causing nested writes to reach Object.prototype in the main n8n process and disrupt later requests. The affected function is summarizeWorkflowStructure in packages/@n8n/instance-ai/src/tools/workflows/summarize-workflow.ts. This issue is fixed in versions 2.37.7 and 2.38.2.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 48% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
N8
n8n · n8n-io
< 2.37.7; >= 2.38.0, < 2.38.2 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-86078
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-86078
Release Notes
https://github.com/n8n-io/n8n/releases/tag/n8n@2.37.7
Release Notes
https://github.com/n8n-io/n8n/releases/tag/n8n@2.38.2
Mitigation
https://github.com/n8n-io/n8n/security/advisories/GHSA-679f-58pq-4v2c
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