Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a local attacker to execute arbitrary code or cause a denial of service due to improper bounds checking.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.5",
  "pubDate": "2026-08-13T21:17:44.377Z",
  "pubdate": "2026-08-13T21:17:44.377Z",
  "executiveSummary": "A vulnerability related to improper bounds checking has been identified in IBM i versions 7.6, 7.5, 7.4, and 7.3. This security flaw introduces significant risk to the integrity, availability, and confidentiality of the underlying operating system components.\nThe primary vulnerability type is an out-of-bounds error stemming from insufficient validation of input or memory index boundaries during internal processing. Successfully exploiting this security weakness allows a localized threat actor to execute arbitrary code with elevated privileges or trigger a denial of service state, leading to system crashes or unresponsiveness.\nThe affected products are restricted to specific releases of the IBM i operating system. The risk implications are severe due to the potential for complete system compromise or localized operational disruption.\nRegarding attacker capabilities, the threat actor must already have local access to the target system to initiate the exploit sequence. The exploitation requirements dictate that the adversary must interact directly with vulnerable internal components or interfaces that lack strict boundary enforcement, bypassing standard security controls to manipulate system memory or execute unauthorized system commands.",
  "technicalDetails": "The root cause of this vulnerability lies in improper bounds checking within vulnerable software modules of the IBM i operating system. When handling specific inputs, memory references, or internal data structures, the affected component fails to adequately verify that the targeted memory offsets or buffer sizes fall within allocated and safe boundaries.\nThe vulnerable components reside within core operating system libraries and utilities across IBM i versions 7.6, 7.5, 7.4, and 7.3. Network exposure is non-existent for remote exploitation vectors, as the attack surface requires local access to the system. Consequently, network protocols and remote services are not directly implicated in the initial phase of the attack flow.\nAuthentication requirements and privilege requirements dictate that an attacker must possess local execution capabilities on the host. While specialized administrative privileges may not be strictly necessary to initiate the attack vector, the local posture implies that the actor has already established a foothold or user session on the machine.\nThe step-by-step attack flow begins with the local attacker supplying crafted input or interacting with a vulnerable local interface designed to process internal data structures. Because the application or operating system component fails to perform adequate boundary validation, the provided input or manipulated offset references exceed the intended memory boundaries.\nThis condition leads to memory corruption, out-of-bounds reads or writes, and unsafe pointer manipulation. Depending on the exact nature of the memory corruption, the payload behavior can manifest in two primary ways: first, the destabilization of the runtime environment results in a denial of service, crashing critical processes or the entire operating system kernel.\nSecond, a sophisticated attacker can leverage the precise memory corruption primitive to overwrite adjacent memory structures, inject malicious shellcode, and hijack the control flow execution path. Post-exploitation impact includes the execution of arbitrary code in the context of the vulnerable process or system runtime, allowing the attacker to escalate privileges, tamper with sensitive operating system files, install persistent backdoors, or completely compromise the administrative domain of the IBM i system."
}