| Component | n8n |
| Severity | medium (CVSS 4.3) |
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
| Published (NVD) | 2026-08-20 |
| Last modified | 2026-09-01 |
| Affected versions | n8n < 1.123.69 n8n >= 2.33.0, < 2.33.4 n8n = 2.34.0 |
| Fixed in | 1.123.69, 2.33.4 |
| Weakness | CWE-918 |
| CISA KEV | not listed |
NVD 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).
What to do
- Upgrade n8n to
1.123.69or later (or the patched release of your branch: 2.33.4). - Do not expose the component's API or UI to the internet without authentication in front of it.
Sources
- NVD: CVE-2026-77069
- https://github.com/n8n-io/n8n/security/advisories/GHSA-c4f6-59xq-95ww
- https://www.vulncheck.com/advisories/n8n-before-ssrf-protection-bypass-via-oauth2
Read more
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