CVE-2026-82067 Overview
CVE-2026-82067 is an authorization bypass vulnerability in MongoDB Server. The flaw stems from improper handling of case sensitivity in the configuration validation component. Under certain configuration conditions, the authorization subsystem remains disabled during server startup even when administrators intend to enable it. An unauthenticated attacker with network access to an affected deployment can perform arbitrary administrative operations. This grants full access to data confidentiality, integrity, and availability. The weakness is classified as Improper Handling of Case Sensitivity [CWE-178].
Critical Impact
Unauthenticated network attackers can execute arbitrary administrative operations against MongoDB deployments where the authorization subsystem silently fails to activate at startup.
Affected Products
- MongoDB Server (see vendor advisory for specific affected versions)
- Deployments using configuration files with case-sensitive authorization directives
- Self-managed MongoDB instances relying on configuration-based access control
Discovery Timeline
- 2026-09-08 - CVE-2026-82067 published to NVD
- 2026-09-08 - Last updated in NVD database
Technical Details for CVE-2026-82067
Vulnerability Analysis
The vulnerability resides in the MongoDB Server configuration validation logic. When administrators specify authorization settings, the parser fails to normalize the case of certain configuration keys or values. A mismatch between the expected canonical form and the supplied string causes the validator to accept the input without applying the intended security control. The server then starts with authorization defaulted to a disabled state. Clients connecting to the exposed instance are treated as unauthenticated administrators with full database privileges. Because no error is raised, operators may believe access control is active while the deployment accepts arbitrary commands from any network peer. Refer to the MongoDB Bug Report SERVER-131229 for vendor-provided technical detail.
Root Cause
The root cause is inconsistent string comparison inside the configuration validation component. Case-sensitive matching against expected directive names or enumerated values allows semantically equivalent input to bypass the code path that activates authorization. This aligns with [CWE-178] Improper Handling of Case Sensitivity.
Attack Vector
Exploitation requires only network reachability to the MongoDB Server port, typically TCP 27017. No credentials, user interaction, or elevated privileges are required. An attacker connects with a standard MongoDB client and issues administrative commands directly, including reading arbitrary collections, modifying documents, creating users, or dropping databases.
No verified proof-of-concept code is publicly available. See the MongoDB Bug Report SERVER-131229 for authoritative technical detail.
Detection Methods for CVE-2026-82067
Indicators of Compromise
- MongoDB server logs showing successful administrative operations without prior authentication events
- Unexpected creation, modification, or deletion of user accounts within the admin database
- Outbound data transfer spikes from MongoDB hosts to unfamiliar destinations
- Startup log entries indicating authorization is disabled despite security.authorization: enabled being present in configuration
Detection Strategies
- Audit each MongoDB instance at startup by connecting locally and running db.adminCommand({getCmdLineOpts: 1}) to confirm the effective authorization state
- Compare the running configuration against the declared configuration file to detect silent parser divergence
- Enable and centralize MongoDB audit logs, then alert on administrative commands executed by connections lacking an authenticated principal
Monitoring Recommendations
- Ingest MongoDB server and audit logs into a centralized analytics platform for correlation with network telemetry
- Baseline expected administrative command volume per instance and alert on deviation
- Monitor for MongoDB port exposure to untrusted networks using external attack surface scans
How to Mitigate CVE-2026-82067
Immediate Actions Required
- Inventory all MongoDB Server deployments and verify at runtime that authorization is enabled using db.adminCommand({getCmdLineOpts: 1})
- Restrict network access to MongoDB ports so only trusted application hosts can connect, using firewalls or security groups
- Apply the vendor-supplied patch as soon as it is available for your MongoDB Server branch
- Rotate credentials and audit user collections on any instance suspected of having started without authorization
Patch Information
MongoDB has tracked this issue as SERVER-131229. Consult the MongoDB Bug Report SERVER-131229 for fixed version information and upgrade guidance. Deploy the patched release for your supported branch through standard change management.
Workarounds
- Normalize configuration file directives to the exact case documented by MongoDB, including keys such as security.authorization and values such as enabled
- Enforce authorization on the command line using --auth in addition to configuration file settings so the subsystem activates through a second code path
- Bind MongoDB to loopback or private interfaces only using net.bindIp until the patch is applied
- Place MongoDB instances behind a network segment that requires mutual TLS or VPN authentication
# Verify authorization is active on a running MongoDB instance
mongosh --host 127.0.0.1 --eval 'db.adminCommand({getCmdLineOpts: 1}).parsed.security'
# Enforce authorization at startup regardless of config parsing
mongod --auth --bind_ip 127.0.0.1,10.0.0.10 --config /etc/mongod.conf
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
