n8n before 2.28.0 (and before 2.27.4 on the 2.27.x branch) registers the DELETE /${restEndpoint}/test-webhook/:id endpoint before authentication middleware is applied, allowing any unauthenticated network caller who knows a workflow ID to cancel that workflow's active test webhook registration. The impact is limited to disrupting in-progress test sessions; production webhooks, persistent workflow state, and stored data are not affected.
https://www.vulncheck.com/advisories/n8n-before-authentication-bypass-via-test-webhook
https://github.com/n8n-io/n8n/security/advisories/GHSA-33q9-f52j-gc75
Published: 2026-07-22
Updated: 2026-07-22
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N
Severity: Medium
Base Score: 5.3
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Severity: Medium
Base Score: 6.3
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Severity: Medium