CVE-2026-75159 in BI Connector
Summary
by MITRE • 08/27/2026
An unauthenticated client that can reach a MongoDB Connector for BI deployment configured with Kerberos authentication may cause mongosqld to terminate when a crafted authentication exchange encounters a specific GSSAPI error-handling condition. This can interrupt BI Connector availability until the process restarts.
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability described involves a critical denial of service flaw within the MongoDB Connector for Business Intelligence, specifically affecting deployments that utilize Kerberos authentication via the Simple and Protected GSS-API Negotiation Mechanism. An unauthenticated attacker who possesses network connectivity to the mongosqld process can exploit this weakness by initiating an authentication exchange containing crafted data designed to trigger a specific error-handling condition within the underlying GSSAPI library or implementation. This flaw is not merely a logical bug but represents a failure in robust input validation and exception handling during the complex handshake procedures required for Kerberos-based identity verification. The attacker does not need valid credentials, which significantly lowers the barrier to entry for exploitation, allowing any entity with network access to potentially disrupt service availability.
From a technical perspective, the root cause lies in how the mongosqld process manages state and errors during the GSSAPI negotiation phase. When the crafted authentication exchange is processed, it leads to an unhandled exception or a fatal error condition that causes the application thread handling the connection to crash. This results in the termination of the entire mongosqld process rather than just dropping the specific client connection. Such behavior indicates a lack of defensive programming practices where expected failure modes are not gracefully caught and logged, but instead propagate as unrecoverable errors leading to process exit. The severity is compounded by the fact that Kerberos authentication is often used in enterprise environments for centralized identity management, meaning this vulnerability targets infrastructure components critical for secure data access.
The operational impact of this vulnerability is a complete interruption of Business Intelligence services provided through MongoDB Connector for BI. Since the mongosqld process terminates upon exploitation, all active and pending connections are severed immediately. This leads to a service outage that affects downstream reporting tools, dashboards, and analytics applications relying on real-time or near-real-time data access from MongoDB databases. The recovery requires manual intervention to restart the service, introducing downtime and potential data inconsistency if transactions were in progress at the time of the crash. In high-availability setups, while other nodes might take over traffic, this vulnerability can be used as a vector for sustained denial-of-service attacks against specific cluster members or load balancers targeting these endpoints.
This flaw aligns with Common Weakness Enumeration (CWE) categories such as CWE-20 Improper Input Validation and CWE-755: Improper Handling of Exceptional Conditions, which highlight the failure to properly validate external inputs and handle error states gracefully. In terms of threat modeling and attack patterns, this vulnerability maps to MITRE ATT&CK technique T1499 Endpoint Denial of Service, specifically under sub-techniques involving application exhaustion or resource consumption through crash-inducing payloads. The unauthenticated nature of the exploit places it in a high-risk category for external-facing services, as remote code execution is not required; simple network access suffices to degrade service availability.
Mitigation strategies should focus on both immediate remediation and long-term architectural improvements. Administrators must apply vendor-provided patches or updates that address this specific GSSAPI error-handling flaw in the mongosqld binary. If patching is not immediately feasible, restricting network access to the BI Connector port using firewall rules ensures that only trusted internal networks can initiate connections, thereby mitigating exposure to unauthenticated external attackers. Additionally, implementing strict input validation at any proxy or gateway layer before requests reach the MongoDB service can help filter out malformed authentication packets. Regular security audits of configuration files and dependency versions are essential to ensure that underlying libraries like GSSAPI implementations remain up-to-date with their respective security advisories.