Description

IBM Informix oninit sq_sgkprepare RCE via unchecked SQL Interface length field.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-08-12T20:17:34.857Z",
  "pubdate": "2026-08-12T20:17:34.857Z",
  "executiveSummary": "A remote code execution vulnerability exists within IBM Informix, specifically affecting the oninit executable and the sq_sgkprepare function. The vulnerability arises due to an unchecked length field within the SQL interface protocol, which can lead to memory corruption conditions such as buffer overflows.\nSuccessful exploitation of this flaw allows a remote attacker to execute arbitrary code or commands with the privileges of the vulnerable database service, typically root or informix. This compromise introduces severe security implications, potentially leading to complete system compromise, unauthorized data exfiltration, integrity manipulation, and denial of service across affected IBM Informix database deployments.\nThe attack vector involves sending a maliciously crafted payload over the network targeting the vulnerable SQL interface of the database management system. Exploitation generally requires network connectivity to the Informix database listener port and interaction with the affected protocol handler.\nOrganizations utilizing IBM Informix must apply vendor-supplied patches or security updates immediately upon availability and enforce strict network segmentation to limit exposure of database listener ports to trusted networks only.",
  "technicalDetails": "The vulnerability resides in the oninit binary of IBM Informix, specifically within the internal processing logic handled by the sq_sgkprepare function. The root cause of the flaw is the lack of proper input validation and bounds checking on a length field transmitted via the SQL interface protocol.\nWhen the oninit process parses incoming network traffic containing SQL interface commands, the sq_sgkprepare function ingests data packets and reads the specified length parameter to allocate or copy buffer contents. Because the length field is unchecked, an attacker can supply a value larger than the allocated destination buffer size.\nThe step-by-step attack flow begins with the threat actor establishing a network connection to the IBM Informix database listener port. The attacker then crafts a specialized connection request or SQL interface packet where the length field associated with the sq_sgkprepare routine is intentionally manipulated to exceed expected operational limits.\nUpon transmission, the vulnerable sq_sgkprepare function processes the oversized data, resulting in a stack-based or heap-based buffer overflow. This memory corruption permits the overwriting of adjacent memory structures, function pointers, or saved frame pointers within the process execution context.\nBy carefully constructing the payload, the attacker can redirect execution flow to shellcode contained within the injected data stream. This payload executes directly within the context of the database server process, inheriting its security context and system privileges.\nExploitation requires network access to the database service. Depending on the specific deployment configuration and hardening posture, authentication may or may not be required prior to reaching the vulnerable function, though protocol-level interactions are generally necessary to trigger the sq_sgkprepare parsing logic.\nPost-exploitation impact includes arbitrary command execution, persistence establishment via database or operating system mechanisms, lateral movement within the internal network, and unauthorized access to sensitive database tables and system configurations."
}