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How the CVE Works:
This vulnerability is a TLS certificate validation bypass due to improper Extended Key Usage (EKU) enforcement. On affected systems, the MongoDB server fails to correctly verify the `clientAuth` or `serverAuth` key usage flags during TLS handshakes. When a client connects to a MongoDB server on Windows or Apple OS, the server accepts client certificates that specify an `extendedKeyUsage` but lack the required `clientAuth` purpose. Conversely, a MongoDB server on Apple OS establishing an outbound connection will accept server certificates missing the `serverAuth` EKU. This flaw occurs because the underlying OS-specific TLS libraries do not perform the strict EKU validation that MongoDB’s documentation states is required, unlike the correct validation on Linux. This allows entities with a technically invalid certificate for authentication to successfully connect.
DailyCVE Form:
Platform: MongoDB Server
Version: <7.0.26, <8.0.16, <8.2.2
Vulnerability: EKU Validation Bypass
Severity: Critical
Date: 2025-11-25
Prediction: Patch Available
What Undercode Say:
Analytics:
openssl x509 -in cert.pem -text -noout | grep -A1 "Extended Key Usage" mongod --tlsCAFile ca.pem --tlsCertificateKeyFile server.pem --tlsAllowInvalidCertificates netstat -tlnp | grep 27017
How Exploit:
An attacker with a client certificate lacking `clientAuth` EKU could potentially authenticate to a vulnerable MongoDB instance on Windows/macOS. Similarly, a server with a certificate lacking `serverAuth` could be connected to by a vulnerable MongoDB client on macOS, enabling MITM risks for outbound connections.
Protection from this CVE:
Upgrade MongoDB immediately.
Apply strict network controls.
Use Linux platforms.
Impact:
Authentication Bypass Potential
MITM Risk
Policy Violation
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Sources:
Reported By: nvd.nist.gov
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