SSRF in N8n
CVE-2026-77069
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).
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (19.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 19.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- N8n — versions 2.34.0
- N8n-Io N8n
Weakness classification (CWE)
References
- github.com/n8n-io/n8n/security/advisories/GHSA-c4f6-59xq-95ww (vendor-advisory, Mitigation, Vendor Advisory)
- www.vulncheck.com/advisories/n8n-before-ssrf-protection-bypass-via-oauth2 (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-77069?
- CVE-2026-77069 is a medium-severity vulnerability in N8n, classified under Server-Side Request Forgery (SSRF). CVSS score: 4.3/10. Published 2026-08-20.
- How severe is CVE-2026-77069?
- Medium severity. CVSS v3 base score is 4.3 out of 10.