Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to cause a denial of service due to an integer overflow.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.3",
  "pubDate": "2026-09-04T17:16:55.883Z",
  "pubdate": "2026-09-04T17:16:55.883Z",
  "executiveSummary": "A vulnerability exists in IBM i versions 7.3, 7.4, 7.5, and 7.6 that permits a remote authenticated attacker to induce a denial-of-service (DoS) condition.\nThe vulnerability is rooted in an integer overflow flaw within the underlying system software components of IBM i.\nSuccessful exploitation of this flaw allows an attacker to exhaust system resources or cause service instability, effectively rendering the affected IBM i environment unavailable to legitimate users.\nThis vulnerability requires the attacker to have established an authenticated session with the target system, limiting the immediate risk to internal or privileged actors.\nThe impact is primarily categorized as a disruption of service, which can have significant operational implications in environments relying on continuous IBM i availability.\nNo specific mention of arbitrary code execution capabilities is noted; however, the resulting service interruption necessitates immediate attention to maintain system integrity and uptime.",
  "technicalDetails": "The vulnerability is classified as an integer overflow error, occurring during the processing of specific input data by affected components within the IBM i operating system.\nInteger overflows occur when an arithmetic operation attempts to create a numeric value that exceeds the maximum storage capacity of the integer type allocated by the software. In the context of IBM i, this indicates that the system does not properly validate or constrain input values before performing arithmetic operations, leading to an wrapping effect.\nThe attack flow requires the adversary to initiate a connection and authenticate successfully to the target IBM i environment. Once authentication is established, the attacker sends a specially crafted request or data packet to a vulnerable service or function that performs calculations on the input without sufficient bounds checking.\nWhen the input is processed, the mathematical operation triggers an overflow. This overflow can result in unexpected memory allocation, incorrect loop indexing, or the corruption of critical data structures that manage system operations. The downstream effect of this corruption is an unhandled exception or a system-wide crash, forcing the affected service or the entire LPAR into a non-functional state.\nBecause the vulnerability exists in core IBM i components present in versions 7.3 through 7.6, the attack surface is broad across these environments. The lack of proper boundary checking allows the attacker to force the system into an inconsistent state, causing the service to cease functioning to prevent further instability or as a result of a fatal crash.\nThe exploitation mechanism leverages the trust boundary established by authentication. By successfully authenticating, the attacker bypasses initial network-level perimeter defenses, allowing them to interact directly with the vulnerable internal APIs or system services. The exploitation does not necessarily require highly elevated privileges, provided the attacker has access to the specific function that is susceptible to the arithmetic fault.\nPost-exploitation impact is limited to the denial of service. The system must be restarted or the specific affected service must be recovered to restore normal operations. There is no evidence currently suggesting that this integer overflow leads to memory corruption that can be leveraged for arbitrary code execution, but the disruption remains a critical concern for system availability."
}