Description

An application using the MongoDB BI Connector ODBC Driver may encounter a memory-safety issue when a submitted SQL statement contains an unusually long run of digits following a LIMIT clause. The issue occurs only on connections where the driver's optional prefetch setting is enabled, and stems from the driver copying the digit sequence into a fixed-size internal buffer without checking its length. A user able to influence the numeric portion of a LIMIT clause could cause the hosting application process to terminate unexpectedly or corrupt adjacent memory in that process.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.1",
  "pubDate": "2026-08-28T22:16:54.930Z",
  "pubdate": "2026-08-28T22:16:54.930Z",
  "executiveSummary": "The MongoDB BI Connector ODBC Driver is susceptible to a memory-safety vulnerability characterized as a buffer overflow. This flaw manifests when the driver processes a SQL statement containing an excessively long numeric sequence following a LIMIT clause, provided that the optional prefetch setting is active.\nThe vulnerability occurs due to the lack of bounds checking when the driver copies user-supplied input into a fixed-size internal buffer. An attacker capable of submitting crafted SQL statements can exploit this condition to trigger a process crash (Denial of Service) or potentially corrupt adjacent memory within the application process.\nThe risk implication is significant as it allows for arbitrary memory manipulation, which could theoretically be leveraged for remote code execution depending on the application's memory layout and runtime environment. Successful exploitation requires the ability to influence the SQL query structure, specifically the numeric parameter of a LIMIT clause. This vulnerability affects systems where the ODBC driver is utilized with the prefetch feature enabled, necessitating immediate review of data input sanitization protocols and driver configurations.",
  "technicalDetails": "The vulnerability resides within the internal string handling logic of the MongoDB BI Connector ODBC Driver, specifically in the parsing module responsible for sanitizing and preparing SQL statements for downstream processing. The flaw is triggered exclusively when the optional prefetch configuration is enabled in the driver's connection settings.\nThe root cause is a classic stack or heap-based buffer overflow stemming from an unsafe memory copy operation. When the driver encounters a SQL LIMIT clause, it attempts to extract the integer value following the keyword. The implementation uses a fixed-size stack-allocated buffer to store this digit sequence. However, the code fails to perform adequate length validation before copying the input stream into this internal memory space. By providing an unusually long string of digits, an attacker can exceed the allocated bounds of the buffer.\nThe attack flow begins when an application accepts untrusted input that is subsequently incorporated into a SQL query sent through the MongoDB BI Connector. An attacker injects a maliciously crafted LIMIT parameter consisting of a large sequence of digits. When the ODBC driver processes this query with prefetch enabled, the parsing function invokes a copy routine—likely a standard C library function such as strcpy or a custom memmove equivalent—without checking the source length against the destination buffer size. The overflow overwrites adjacent memory, which may include return addresses, function pointers, or critical heap metadata.\nThe impact of this memory corruption is twofold. First, it can lead to an immediate access violation or segmentation fault, resulting in the abrupt termination of the hosting application process, thereby facilitating a Denial of Service. Second, in more complex attack scenarios, an adversary might carefully craft the overflow payload to overwrite return pointers or control structures. If the application environment lacks modern exploit mitigations like Address Space Layout Randomization (ASLR) or Data Execution Prevention (DEP), this could result in arbitrary code execution with the privileges of the application process. Because the processing occurs at the driver level, the vulnerability is potentially accessible via any interface that allows the submission of SQL queries to the MongoDB BI Connector, regardless of the authentication level required by the database, provided the attacker can reach the application's query injection point."
}