Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to cause a denial of service and potentially obtain sensitive information due to a stack-based buffer overflow.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.6",
  "pubDate": "2026-08-13T20:17:15.187Z",
  "pubdate": "2026-08-13T20:17:15.187Z",
  "executiveSummary": "A stack-based buffer overflow vulnerability exists in IBM i versions 7.6, 7.5, 7.4, and 7.3, potentially allowing remote attackers to compromise system availability and confidentiality. The flaw stems from improper boundary checks within vulnerable components of the operating system, enabling threat actors to supply specially crafted inputs that exceed pre-allocated stack memory buffers. Successful exploitation of this security defect allows a remote attacker to trigger a denial of service condition, disrupting critical system operations, and potentially facilitating the unauthorized disclosure of sensitive system information residing in adjacent memory regions. The risk implications are severe due to the core operating system context affected, which underpins enterprise workloads. While specific authentication or privilege requirements are dictated by the underlying network service exposing the flaw, the capability to execute attacks remotely expands the potential threat surface across enterprise environments. Remediation requires applying official vendor-supplied security fixes or patches as soon as they become available from IBM to prevent exploitation.",
  "technicalDetails": "The vulnerability is fundamentally rooted in a classic stack-based buffer overflow condition affecting IBM i 7.6, 7.5, 7.4, and 7.3. This security defect occurs when vulnerable binaries or internal OS services accept data input from network-connected users without properly validating the length of the incoming data relative to the destination buffer allocated on the call stack. When an attacker submits an oversized payload designed to exceed the buffer boundaries, the excess data overwrites adjacent stack memory structures, including critical execution control data such as saved frame pointers and return addresses.\nFrom an attack flow perspective, a remote threat actor leverages network exposure by transmitting a maliciously crafted payload targeting the vulnerable service or component. Upon ingestion of the oversized data stream, the lack of programmatic boundary enforcement triggers memory corruption. If the payload is structured to manipulate the instruction pointer or corrupt internal data structures, it disrupts the normal execution flow of the process, immediately resulting in a denial of service through application crashes or operating system instability. Furthermore, depending on the memory layout and the specific data exposed during or after the corruption event, the crafted input can facilitate the unauthorized readback or leakage of sensitive information residing on the stack.\nThe affected components comprise internal operating system modules and services within IBM i 7.6, 7.5, 7.4, and 7.3 that process untrusted network inputs. The attack vector is strictly remote, meaning an adversary does not require physical access or prior execution privileges on the host system, provided network connectivity to the vulnerable service is established. Although explicit granular privilege requirements vary based on the targeted network service interface, the potential for total service disruption and sensitive data exposure presents a significant security risk to the affected infrastructure. Payload behavior focuses predominantly on memory exhaustion, corruption, and information disclosure rather than direct remote code execution, though the overwrite of stack control data inherently introduces severe system integrity risks."
}