Description
n8n before 1.123.69, 2.33.4, and 2.34.1 contains an SSRF protection bypass in the OAuth2 credential authorization-code-to-access-token exchange. While OAuth2 discovery and dynamic-client-registration requests use n8n's SSRF-protected HTTP client, the token exchange uses a separate client with no SSRF guard. A user with credential-creation permissions can set the access-token URL to an internal address and complete the OAuth2 flow, causing n8n to send a fixed-shape token-exchange POST to that target and reflect its response body back to the attacker (limited to what the target returns to this specific request).
Metrics
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| n8n-io | n8n | < 1.123.69 |
| n8n-io | n8n | >= 2.34.0, < 2.34.1 |
| n8n-io | n8n | >= 2.0.0, < 2.33.4 |
References
- https://github.com/n8n-io/n8n/security/advisories/GHSA-c4f6-59xq-95wwMitigation, Vendor Advisory
- https://www.vulncheck.com/advisories/n8n-before-ssrf-protection-bypass-via-oauth2Third Party Advisory
Timeline
- Published
- Aug 20, 2026
- Last modified
- Sep 1, 2026
- NVD status
- Analyzed