CVE-2026-86078 json
n8n: Prototype Pollution via Workflow Structure Summary Can Lead to Denial of Service
published 2026-09-08 2 mo ago modified 2026-09-11 58 d ago also GHSA-679f-58pq-4v2c , EUVD-2026-74278
- cvss
- 6.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 48%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- npm n8n 2.37.7, 2.38.2
- n8n n8n 2.37.7, 2.38.2
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 1 mo ago
Exploit prediction
0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.0 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| CNA | 4.0 | 6.0 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | n8n | >=2.38.0, <2.38.2 <2.37.7 |
2.38.2 2.37.7 |
Affected products
- n8n-io n8n
Classification
- Weakness
-
- CWE-1321 Improperly Controlled Modification of Object Prototype Attributes
References
-
github.com
/n8n-io/n8n/security/advisories/GHSA-679f-58pq-4v2c
web, mitigation, vendor-advisory
-
github.com
/n8n-io/n8n/releases/tag/n8n@2.37.7
web, release-notes
-
github.com
/n8n-io/n8n/releases/tag/n8n@2.38.2
web, release-notes
-
nvd.nist.gov
/vuln/detail/CVE-2026-86078
advisory
-
github.com
/n8n-io/n8n
package
Sources
- CVE List CVE-2026-86078
- GitHub Advisory GHSA-679f-58pq-4v2c
- NVD CVE-2026-86078
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.