High severity · published Oct 28, 2026
CVE-2026-118678
n8n before 2.41.4 and 2.42.1 Prototype Pollution DoS via Workflow History Compaction
New
7.1
CVSS
–
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
N8
n8n · n8n-io
before 2.41.4; 2.42.0 before 2.42.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-118678
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-118678
vendor-advisory
https://github.com/n8n-io/n8n/security/advisories/GHSA-fvv4-gmv9-xqf5
third-party-advisory
https://www.vulncheck.com/advisories/n8n-before-2.41.4-and-2.42.1-prototype-pollution-dos-via-workflow-history-compaction
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