CVE-2026-118678
n8n before 2.41.4 and 2.42.x before 2.42.1 contains a prototype pollution vulnerability that allows low-privileged users to alter built-in object behaviour by saving workflows with specially named connection keys. Attackers can add keys such as __proto__ to workflow connections, which the periodic history compaction task processes, causing logins and writes to fail with server errors.
- Score
- CVSS 4.0 7.1 High
- Status
- Deferred - disclosure@vulncheck.com
- Published
- 2026-10-28
- Last modified
- 2026-10-28
- Weaknesses
- CWE-1321
Affected products
References
- https://github.com/n8n-io/n8n/security/advisories/GHSA-fvv4-gmv9-xqf5
- https://www.vulncheck.com/advisories/n8n-before-2.41.4-and-2.42.1-prototype-pollution-dos-via-workflow-history-compacti…
