Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to execute arbitrary code due to an out-of-bounds write.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-12T18:17:25.867Z",
  "pubdate": "2026-08-12T18:17:25.867Z",
  "executiveSummary": "An out-of-bounds write vulnerability has been identified in IBM i versions 7.6, 7.5, 7.4, and 7.3, posing significant security risks to enterprise environments. This memory corruption flaw allows a remote attacker to execute arbitrary code on the underlying operating system.\nThe vulnerability stems from improper bounds checking during data processing within the affected software components of IBM i. If successfully exploited, an unauthorized remote threat actor can leverage this weakness to corrupt memory structures, potentially bypassing security controls and executing arbitrary payloads with system-level privileges.\nThe impact of successful exploitation includes complete system compromise, unauthorized access to sensitive data, and potential disruption of critical business operations managed by the IBM i environment.\nGiven the remote vector and the capability for arbitrary code execution, this vulnerability demands immediate prioritization by system administrators and security teams responsible for IBM i infrastructure. Remediation requires adherence to vendor-supplied updates and hardening guidelines to mitigate unauthorized access and potential weaponization of the out-of-bounds write condition.",
  "technicalDetails": "The vulnerability is classified as an out-of-bounds write, a critical memory corruption flaw occurring when software writes data past the intended boundary of a designated buffer or memory allocation. In the context of IBM i versions 7.6, 7.5, 7.4, and 7.3, this flaw resides within specific internal data processing components handling remote inputs.\nRoot Cause Analysis: The underlying defect is insufficient validation and boundary verification of input sizes prior to memory write operations. When an interacting component processes maliciously crafted data packets or parameters supplied by an external source, the system fails to accurately calculate the destination buffer dimensions. Consequently, incoming data overflows the allocated memory region, overwriting adjacent memory segments, heap metadata, or critical stack control data.\nAttack Flow and Exploitation Method: An unauthenticated or remote attacker initiates exploitation by transmitting specially crafted network requests containing malicious payloads to vulnerable services running on the IBM i host. Upon receiving the input, the vulnerable parsing or processing routine attempts to store the oversized data into a fixed-size buffer without performing adequate bounds checks.\nAs the out-of-bounds write occurs, the attacker strategically corrupts adjacent memory pointers or function pointers. By carefully orchestrating the contents of the overflow, the attacker can hijack the control flow of the application when execution reaches the modified pointers. This redirection allows the seamless execution of shellcode or arbitrary code embedded within the payload.\nPrivileges and Network Exposure: The vulnerability is exploitable remotely over network protocols interfacing with the affected IBM i subsystems. Depending on the specific service exposed, exploitation may not require prior authentication, significantly lowering the attack barrier for external adversaries. Successful exploitation grants the attacker the execution privileges of the compromised process, which frequently operates with elevated or root-level permissions inherent to core operating system services.\nPost-Exploitation Impact: Once arbitrary code execution is achieved, the attacker can execute system commands, deploy persistent backdoors, escalate privileges further if necessary, exfiltrate confidential databases hosted on the IBM i system, or pivot deeper into the corporate network. The integrity, confidentiality, and availability of the entire operating environment are severely compromised."
}