CVE-2026-77586 Overview
CVE-2026-77586 is a SQL injection vulnerability in the MongoDB Connector for BI. The connector places MongoDB object names such as collections, fields, and indexes into quoted identifiers within the DDL text returned by SHOW CREATE statements. The connector does not escape the identifier delimiter when constructing this output. A user with write permission on a sampled MongoDB collection can craft an object name that closes the quoted identifier early and appends arbitrary SQL. When an operator or automated pipeline replays the generated DDL against a SQL server, the injected statements execute with the privileges of that session.
Critical Impact
An authenticated MongoDB writer can inject SQL that later executes with the privileges of a downstream SQL server session, enabling data exposure, tampering, or destructive commands.
Affected Products
- MongoDB Connector for BI
- Downstream SQL servers that consume SHOW CREATE output from the connector
- Automated tooling that replays connector-generated DDL statements
Discovery Timeline
- 2026-08-28 - CVE-2026-77586 published to NVD
- 2026-08-31 - Last updated in NVD database
Technical Details for CVE-2026-77586
Vulnerability Analysis
The MongoDB Connector for BI exposes MongoDB collections as relational tables to SQL-speaking clients. When a client issues SHOW CREATE, the connector generates DDL text describing the mapped schema. The connector embeds MongoDB object names (collection, field, and index names) directly into quoted SQL identifiers in that output. Because the connector does not escape the identifier delimiter, an attacker-supplied name containing a delimiter character breaks out of the quoted identifier context. Subsequent characters become interpretable SQL tokens rather than parts of a name. This flaw is classified under [CWE-89] (Improper Neutralization of Special Elements used in an SQL Command).
Root Cause
The connector treats MongoDB identifiers as trusted strings when serializing DDL. Identifier quoting is applied by simple string wrapping, without doubling or escaping any embedded delimiter characters. Any MongoDB writer can introduce such a character through normal document, collection, or index creation.
Attack Vector
An attacker requires write access to a MongoDB collection that the BI Connector samples. The attacker creates a collection, field, or index whose name contains the identifier delimiter followed by attacker-controlled SQL. When an operator later runs SHOW CREATE against the connector and pipes the output to a SQL server, the SQL server executes the injected statements. The impact is bounded by the privileges of the replaying session, which in administrative pipelines is often high.
Because no synthetic exploit code has been verified against this advisory, refer to the MongoDB BI Connector Release Notes for authoritative technical detail.
Detection Methods for CVE-2026-77586
Indicators of Compromise
- MongoDB collection, field, or index names containing backtick, double-quote, or other SQL identifier delimiter characters.
- SHOW CREATE output that contains unexpected SQL statements such as DROP, INSERT, GRANT, or UNION outside of identifier positions.
- SQL server audit logs showing DDL replay sessions executing statements not present in the source schema.
Detection Strategies
- Inspect MongoDB metadata for identifier names containing quoting characters, semicolons, or SQL keywords before they are consumed by the connector.
- Compare generated DDL text against a canonical schema definition and alert on any deviation.
- Log and review every invocation of SHOW CREATE issued against the BI Connector, especially those tied to automated replay pipelines.
Monitoring Recommendations
- Enable query auditing on both the MongoDB deployment and the downstream SQL server to correlate identifier creation with DDL replay events.
- Alert on SQL sessions that execute high-privilege statements immediately after ingesting connector output.
- Track write access to sampled MongoDB collections and treat additions of unusual identifiers as security-relevant events.
How to Mitigate CVE-2026-77586
Immediate Actions Required
- Apply the fixed MongoDB Connector for BI release listed in the vendor release notes as soon as it is available.
- Restrict write access to sampled MongoDB collections to the minimum set of trusted principals.
- Halt automated pipelines that replay SHOW CREATE output against SQL servers until the connector is patched.
Patch Information
Review the MongoDB BI Connector Release Notes for the fixed version and upgrade guidance. Apply the patched build to all connector instances before restoring automated DDL replay workflows.
Workarounds
- Manually review SHOW CREATE output before replaying it, and reject any statement that contains SQL tokens outside identifier positions.
- Execute replayed DDL under a low-privilege SQL account that lacks rights to modify data or grant permissions.
- Enforce a naming policy on MongoDB collections, fields, and indexes that rejects identifier delimiter characters at ingest time.
- Isolate the BI Connector on a network segment that only accepts queries from vetted analytics clients.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.