Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to execute arbitrary code due to a buffer overflow.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.1",
  "pubDate": "2026-08-13T20:17:18.780Z",
  "pubdate": "2026-08-13T20:17:18.780Z",
  "executiveSummary": "A buffer overflow vulnerability exists within IBM i versions 7.6, 7.5, 7.4, and 7.3, presenting a significant security risk to enterprise environments. This memory corruption flaw allows an unauthenticated remote attacker to execute arbitrary code with elevated privileges, bypassing system security controls entirely.\nThe vulnerability stems from improper bounds checking during the processing of input data within the affected component. When a remote attacker submits a specially crafted payload exceeding the allocated buffer size, memory corruption occurs. This manipulation can overwrite adjacent memory structures, including stack frames and control data, enabling control flow hijacking.\nThe potential impact includes total system compromise, unauthorized data access, persistence establishment, and disruption of critical business operations. Exploitation requires network connectivity to the vulnerable service, but no prior user interaction or authentication is explicitly required based on the remote attack vector.\nOrganizations utilizing the affected IBM i versions face critical exposure until vendor-supplied patches or workarounds are applied. Immediate remediation is strongly advised to prevent active exploitation and maintain the integrity of core operational systems.",
  "technicalDetails": "The vulnerability is classified as a buffer overflow, specifically occurring due to inadequate validation of input lengths before copying data into fixed-size memory buffers within IBM i 7.6, 7.5, 7.4, and 7.3. The root cause lies in legacy memory management routines that fail to enforce strict boundary checks on incoming network data streams.\nExploitation is achieved by transmitting a maliciously crafted packet or input sequence over the network to the vulnerable service listening on the target system. As the application processes the input, the oversized data spills beyond the boundaries of the intended buffer, corrupting adjacent stack variables, saved frame pointers, and the return instruction pointer.\nThe step-by-step attack flow begins with the remote attacker performing reconnaissance to identify an exposed service running on the vulnerable IBM i instance. Upon identifying the target endpoint, the attacker constructs a specialized payload containing shellcode designed to execute arbitrary system commands or establish a reverse shell. The attacker then transmits this payload via the network protocol handled by the vulnerable component.\nUpon receipt, the vulnerable function attempts to ingest the oversized input into a statically allocated memory buffer without validating the input length. The resulting buffer overflow overwrites the execution stack. When the affected function attempts to return execution control, the modified return pointer directs the instruction pointer to the attacker-supplied shellcode embedded within the payload.\nExecution occurs within the context of the service process, which typically operates with high privileges on the IBM i operating system. Consequently, successful exploitation grants the attacker the ability to execute arbitrary code, manipulate system resources, read sensitive files, and pivot deeper into the network architecture without requiring valid authentication credentials or local privilege escalation steps."
}