Overview
CVE-2025-12893 is a medium-severity vulnerability affecting MongoDB servers running on Windows and Apple operating systems. This flaw exposes a weakness in TLS certificate validation, potentially allowing unauthorized clients and servers to establish connections. Specifically, the issue involves improper handling of Extended Key Usage (EKU) requirements during TLS handshakes. This can lead to insecure connections being established even when the presented certificate does not meet the documented EKU standards.
Technical Details
The vulnerability manifests in two key scenarios:
- Client Authentication: On Windows and Apple systems, MongoDB servers may accept client certificates during a TLS handshake even if the certificate specifies `extendedKeyUsage` but is missing `extendedKeyUsage = clientAuth`. This allows clients with improperly configured certificates to authenticate successfully.
- Server Authentication (Egress Connections): On Apple systems, MongoDB servers establishing egress TLS connections may accept server certificates that specify `extendedKeyUsage` but are missing `extendedKeyUsage = serverAuth`. This allows the MongoDB server to connect to potentially malicious or compromised servers presenting improperly configured certificates.
- Linux Systems: Notably, the expected validation behavior functions correctly on Linux systems for both Client and Server authentication.
The root cause lies in the incorrect implementation of TLS certificate validation logic on Windows and Apple platforms within the affected MongoDB versions. The system fails to enforce the necessary EKU constraints, leading to the acceptance of certificates that should have been rejected.
CVSS Analysis
- Severity: MEDIUM
- CVSS Score: 4.2
While rated as medium severity, the impact can be significant if exploited. A CVSS score of 4.2 indicates a moderate level of concern, primarily due to the need for an attacker to present a certificate (even if improperly configured) and the localized nature of the vulnerability (Windows and Apple). However, the potential for unauthorized access or data interception warrants immediate attention.
Possible Impact
Successful exploitation of CVE-2025-12893 can lead to:
- Unauthorized Access: Malicious clients could gain unauthorized access to the MongoDB database, potentially leading to data breaches and manipulation.
- Man-in-the-Middle Attacks: Compromised servers could intercept and manipulate data transmitted between the MongoDB server and legitimate clients.
- Data Exfiltration: Attackers could exfiltrate sensitive data from the database.
- Denial of Service: In some scenarios, exploiting the vulnerability could lead to a denial of service condition.
Mitigation and Patch Steps
The recommended mitigation is to upgrade your MongoDB server to one of the following versions:
- MongoDB Server v7.0.26 or later
- MongoDB Server v8.0.16 or later
- MongoDB Server v8.2.2 or later
Applying the latest patch is crucial to ensure proper TLS certificate validation and protect your MongoDB deployments from potential attacks. After patching, it’s recommended to review and update your client and server certificates to ensure they conform to the expected EKU requirements.
If immediate patching is not feasible, consider implementing network-level access controls to restrict access to the MongoDB server to only trusted clients and servers. This can help reduce the attack surface and mitigate the risk of exploitation.
