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).
{
"cna_assigner": "VulnCheck",
"cwe_ids": [
"CWE-918"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77069.json"
}{
"cpe": [
"cpe:2.3:a:n8n:n8n:*:*:*:*:*:node.js:*:*",
"cpe:2.3:a:n8n:n8n:2.34.0:*:*:*:*:node.js:*:*"
],
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "1.123.69"
},
{
"introduced": "2.33.0"
},
{
"fixed": "2.33.4"
},
{
"introduced": "2.34.0"
},
{
"last_affected": "2.34.0"
}
],
"source": [
"CPE_RANGE",
"CPE_STRING"
]
}