CVE-2026-86078
CVE-2026-86078 — n8n: Prototype Pollution via Workflow Structure Summary Can Lead to Denial of Service
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.
Published Updated Sources: cvelistV5, GitHub_M
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
0%
chance of exploitation in 30 days
CVSS base
6
MEDIUM
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script all four kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component
Affected scope
The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.
Vendors (1)
Products (1)
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 6 | CVSS 4.0 | MEDIUM | — | — | cvelistV5 |
Weakness & attack patterns
- CWE-1321
Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.
- T1574.010Hijack Execution Flow: ServicesFile Permissions Weakness
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Search application, proxy, and WAF logs for requests touching /@n8n/instance-ai/src/tools/workflows/summarize-workflow.ts.
References
3 on the record
- github.com/n8n-io/n8n/security/advisories/GHSA-679f-58pq-4v2c
x_refsource_CONFIRM
- github.com/n8n-io/n8n/releases/tag/[email protected]
x_refsource_MISC
- github.com/n8n-io/n8n/releases/tag/[email protected]
x_refsource_MISC
Elsewhere on this site
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.