CVE-2026-77184 in BI Connector
Summary
by MITRE • 08/28/2026
In MongoDB Connector for BI, the description text of a collection's JSON schema validator is incorporated into the comment text of the DDL returned by SHOW CREATE statements without complete escaping of backslash characters. A user with permission to modify a collection's schema validator, in deployments configured to build their SQL schema from those validators, can cause additional SQL text to be embedded in that generated output. If an operator or automated tool later replays that generated statement against a SQL server, the additional text is executed with the privileges of that session.
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Analysis
by VulDB Data Team • 08/28/2026
The vulnerability identified within MongoDB Connector for BI represents a critical injection flaw stemming from improper neutralization of special elements during data processing. Specifically, when a collection's JSON schema validator includes descriptive text containing backslash characters, these characters are not adequately escaped before being incorporated into the comment section of Data Definition Language statements generated by SHOW CREATE commands. This technical oversight occurs in deployments where the SQL schema is dynamically constructed based on MongoDB schema validators, creating a direct pathway for malicious actors to manipulate database structure definitions. The core issue lies in the failure to sanitize input data that originates from user-controlled fields within the JSON schema validator configuration, allowing special characters like backslashes to persist and alter the interpretation of subsequent SQL commands.
From an operational perspective, this flaw enables a significant privilege escalation scenario for users who possess permission to modify collection schemas but do not inherently have high-level administrative rights over the underlying relational database engine. By crafting a malicious JSON schema validator that includes carefully constructed text with embedded backslashes, an attacker can inject arbitrary SQL code into the generated DDL output. When this compromised statement is subsequently executed by a privileged operator or an automated deployment tool against the target SQL server, the injected payload runs with the full privileges of that executing session. This effectively bypasses standard access controls and allows for unauthorized data manipulation, structural changes to the database schema, or potentially remote code execution depending on the capabilities exposed through the specific SQL dialect being used.
This vulnerability aligns closely with CWE-79, which covers Improper Neutralization of Input During Web Page Generation known as Cross-site Scripting, although in this context it manifests as SQL Injection due to the backend database interaction. It also maps to ATT&CK technique T1059 Command and Scripting Interpreter, specifically through indirect command execution via injected scripts within legitimate administrative commands. The attack vector relies on social engineering or prior compromise of schema management privileges rather than direct network exploitation, making it a high-risk insider threat scenario that is difficult to detect without rigorous input validation monitoring.
Mitigation strategies must focus on implementing strict output encoding and parameterization for all dynamically generated SQL statements derived from MongoDB schemas. Developers should ensure that any text extracted from JSON validators undergoes thorough sanitization before being embedded into DDL comments or other structural components of the query string. Additionally, organizations should enforce principle of least privilege by separating schema modification rights from database execution privileges where possible. Regular auditing of automated deployment pipelines is essential to detect anomalous SQL patterns generated during schema synchronization processes. Updating MongoDB Connector for BI to versions that address this escaping deficiency is critical, alongside reviewing existing schemas for any pre-existing malicious payloads that may have been injected prior to the patch application.