CVE-2026-109448 in psqlODBC
Summary
by MITRE • 10/12/2026
Integer wraparound in psqlODBC SQLBindParameter allows an application, or an attacker who controls how many parameters the application binds on one statement, to corrupt heap memory. psqlODBC stores the binding count in a signed 16-bit field. Binding parameter number 32768 wraps that count to -32768. Binding parameter 32769 then writes about 2.5 MB of zeros starting 1.25 MB before the binding array, which crashes the application or leaves it running on a corrupted heap. Applications that build parameter lists from untrusted input, such as an IN (?, ?, ...) list, are exposed. Versions before psqlODBC 18.00.0005 are affected.
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Analysis
by VulDB Data Team • 10/12/2026
The vulnerability identified in the PostgreSQL ODBC driver, specifically within the SQLBindParameter function, represents a critical integer wraparound flaw that leads to heap memory corruption. This issue stems from the internal implementation detail where the parameter binding count is stored in a signed 16-bit field. In standard C programming and many database API implementations, such fields are often used for efficiency but introduce risks when handling large numbers of parameters without adequate bounds checking or type conversion safeguards. The core technical flaw occurs because the counter does not account for overflow conditions inherent to fixed-width integer types. When an application attempts to bind a parameter number that exceeds the maximum positive value representable by a signed 16-bit integer, which is 32767, the value wraps around due to two's complement arithmetic rules. Specifically, binding parameter number 32768 causes the internal counter to wrap from its maximum positive value of 32767 down to -32768. This negative index or count subsequently disrupts subsequent memory allocation and write operations associated with that statement handle.
The operational impact of this integer overflow is severe, resulting in out-of-bounds heap writes that can crash the application or leave it running on a corrupted heap state. When parameter number 32769 is bound following the wraparound event, the driver attempts to perform memory operations based on the miscalculated offset derived from the negative count. This results in writing approximately 2.5 megabytes of zeros starting at an address located roughly 1.25 megabytes before the intended binding array buffer. Such a massive out-of-bounds write corrupts adjacent heap metadata and potentially overwrites critical data structures managed by the memory allocator or other application variables. If the overwritten region contains control flow pointers, function addresses, or security-critical flags, an attacker who can influence the number of parameters bound could achieve arbitrary code execution through precise exploitation techniques. Even if immediate code execution is not feasible, the resulting heap corruption typically leads to denial of service via segmentation faults or undefined behavior that destabilizes the entire application process.
This vulnerability primarily affects applications that construct parameter lists dynamically from untrusted input sources. Common scenarios include web applications or API services that accept variable-length IN clauses with placeholders such as IN (?, ?, ...), where the number of question marks is determined by user-supplied data. If an attacker can supply a payload containing more than 32768 parameters, they trigger the integer wraparound condition within psqlODBC. The risk is particularly acute for legacy systems or high-throughput applications that rely on bulk parameter binding for performance optimization but do not implement strict validation on the count of bound parameters before invoking SQLBindParameter repeatedly. Versions prior to 18.00.0005 are susceptible to this flaw, as the fix involves correcting the handling of large parameter counts and ensuring proper bounds checking during the binding process.
From a classification perspective, this vulnerability aligns with CWE-190 Integer Overflow or Wraparound, which describes errors resulting from arithmetic operations that exceed the capacity of an integer type without appropriate checks. The exploitation technique leverages memory corruption to compromise integrity and potentially availability, mapping closely to ATT&CK techniques related to buffer overflow exploits and heap spraying if the attacker aims for code execution. Mitigation strategies must focus on both immediate patching and architectural improvements. Organizations should upgrade psqlODBC to version 18.00.0005 or later immediately upon release to address the underlying integer handling logic. Additionally, developers implementing ODBC interfaces should enforce strict validation of parameter counts before binding operations occur. Implementing a hard limit on the number of parameters allowed per statement can prevent attackers from reaching the overflow threshold. Input sanitization at the application layer is essential, ensuring that any dynamic SQL generation validates the size and structure of incoming data against expected business logic constraints rather than relying solely on driver-level protections.