EUVD-2026-90653
GHSA-qrhv-fqjc-jcmq
Severity by source
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:A/VC:H/VI:H/VA:H/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Requires resolver-registration privilege (PR:H) and a collaborator's active connection flow (AC:H/UI:R); stolen token crosses an authorization boundary (S:C) exposing and letting attacker use others' credentials (C:H/I:H).
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
6DescriptionCVE.org
n8n versions before 2.39.6 and 2.40.0 before 2.40.1 contain a session token leakage vulnerability in the Dynamic Credentials authorize and revoke endpoints. Attackers with resolver registration capability can capture collaborators' session tokens by setting a fallback resolver to an attacker-controlled endpoint during the account connection flow, enabling unauthorized credential access.
Articles & Coverage 1
AnalysisAI
Session token leakage in n8n's Dynamic Credentials authorize and revoke endpoints lets an attacker who already holds resolver-registration privileges point a fallback resolver at an attacker-controlled endpoint and capture a collaborating user's session token once that user completes the account-connection flow, yielding unauthorized credential access. Impact is access-gated rather than open: exploitation requires an authenticated, high-privileged actor plus an independent user interaction, and is realistic mainly on shared or multi-tenant n8n instances where semi-trusted users hold resolver-registration rights, not against a default single-tenant deployment reachable by an unprivileged remote attacker. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires an attacker who already possesses resolver-registration capability within n8n and is limited to deployments using the Dynamic Credentials feature's authorize/revoke endpoints. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is a genuinely serious but access-gated flaw. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Vendor-released patch: upgrade to n8n 2.39.6 or later on the 2.39.x line, or to 2.40.1 or later on the 2.40.x line, per the advisory at https://github.com/n8n-io/n8n/security/advisories/GHSA-rx55-8qhx-4hwx. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory every n8n instance in the environment and confirm which are on versions before 2.39.6 or on 2.40.0 before 2.40.1, then prioritize multi-tenant or shared instances for immediate remediation; temporarily restrict resolver-registration privileges to the smallest possible set of trusted administrators and review recent resolver configuration changes for unexpected or externally pointing fallback endpoints. …
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External POC / Exploit Code
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