Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to cause a denial of service due to an improper buffer write.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.8",
  "pubDate": "2026-08-13T21:17:43.193Z",
  "pubdate": "2026-08-13T21:17:43.193Z",
  "executiveSummary": "An improper buffer write vulnerability has been identified in IBM i versions 7.3, 7.4, 7.5, and 7.6. This security flaw introduces a significant risk of a remote denial of service condition against affected systems.\nThe vulnerability stems from improper memory handling, specifically an improper buffer write operation within the affected software components of the operating system. If successfully exploited, a remote attacker can trigger memory corruption leading to system instability, service disruption, or complete denial of service of the targeted IBM i instance.\nThe risk implications are high due to the potential for unauthenticated remote attackers to disrupt critical enterprise workloads running on the IBM i platform. Exploitation requires network connectivity to vulnerable services exposed by the operating system, allowing threat actors to compromise availability without necessarily requiring valid user credentials or advanced privileges.\nOrganizations utilizing the specified IBM i versions must prioritize monitoring for vendor-supplied patches and implementing compensating network controls to restrict exposure until remediation can be fully applied.",
  "technicalDetails": "The vulnerability is classified as an improper buffer write, a memory safety issue that occurs when software writes data past the boundary of the allocated buffer. In the context of IBM i versions 7.3, 7.4, 7.5, and 7.6, this flaw resides within specific internal processing routines responsible for handling incoming data packets or protocol messages.\nThe root cause of the vulnerability lies in insufficient bounds checking and input validation prior to executing memory write operations. When the system processes maliciously crafted input provided by a remote entity, it fails to adequately verify the size of the incoming data against the pre-allocated memory buffer size. Consequently, the memory write operation exceeds the intended boundaries, resulting in a buffer overflow condition.\nThe exploitation method involves a remote attacker transmitting a specially crafted payload over the network to a vulnerable service running on the IBM i system. The attack flow begins with network reconnaissance to identify exposed services associated with the operating system. Upon identifying a target service, the attacker formulates a malicious payload designed to exceed the capacity of the target buffer.\nAs the vulnerable component processes the incoming malformed request, the improper buffer write is triggered. The payload overwrites adjacent memory regions, which can corrupt critical control data, execution stacks, or heap structures. This unauthorized memory modification inevitably leads to a fatal exception, application crash, or kernel panic, thereby instigating a denial of service condition.\nAuthentication and privilege requirements depend on the specific network service exposed, but remote exploitation typically requires network access to the vulnerable interface without necessitating prior authentication or elevated privileges. The network exposure is directly tied to the accessibility of the affected IBM i services from untrusted networks or the local area network.\nThe post-exploitation impact is primarily concentrated on availability, manifesting as service disruption and potential system-wide crashes requiring administrative intervention or system reboots to restore normal operations."
}