Vulnerabilities / CVE-2026-118678

CVE-2026-118678

Published 2026-10-28 · published (not yet in NVD)

CVE-2026-118678

n8n before 2.41.4 and 2.42.1 Prototype Pollution DoS via Workflow History Compaction

7.1 HIGH
CVSS 4.0 · CNA

0.3%
chance of exploitation in the next 30 days (EPSS; higher than 21% of CVEs)

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.

Scores

7.1CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:NCNA

7.1CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:HCNA

Affected products

n8n-io n8n: < 2.41.4
n8n-io n8n: 2.42.0 to < 2.42.1

Weakness: CWE-1321

Also known as: GHSA-fvv4-gmv9-xqf5

2 references (advisories, patches, write-ups)

https://github.com/n8n-io/n8n/security/advisories/GHSA-fvv4-gmv9-xqf5 · vendor-advisory
https://www.vulncheck.com/advisories/n8n-before-2.41.4-and-2.42.1-prototype-pollution-dos-via-workflow-history-compaction · third-party-advisory

Sources: CVE.org, OSV.dev, FIRST EPSS. Missing ones did not answer or have no record yet.

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