Description

IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a remote attacker to cause a denial of service due to an integer underflow.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-19T20:17:04.270Z",
  "pubdate": "2026-08-19T20:17:04.270Z",
  "executiveSummary": "An integer underflow vulnerability has been identified in IBM AIX 7.2 and 7.3, alongside IBM PowerVM VIOS 4.1.\nThis vulnerability is classified as a denial of service (DoS) flaw that enables a remote attacker to compromise system availability.\nThe risk implications are significant for enterprise environments relying on these operating systems and virtualization platforms, as an unexpected crash or resource exhaustion can disrupt critical workloads hosted on the affected infrastructure.\nThe attacker capabilities involve remote exploitation vectors to trigger the vulnerable condition without necessarily requiring complex privileged access beforehand, depending on the specific network service handling the malformed input.\nExploitation requirements center on sending crafted network traffic or data packets designed to trigger the underlying integer underflow condition within the vulnerable parsing logic or component.\nSuccessful exploitation directly results in service disruption, application termination, or potential kernel/system instability, culminating in a complete denial of service for the targeted IBM AIX or IBM PowerVM VIOS instance.",
  "technicalDetails": "The root cause of the vulnerability resides in an integer underflow condition within internal numerical processing logic of the affected IBM AIX and IBM PowerVM VIOS components.\nAn integer underflow occurs when an arithmetic operation attempts to create a numerical value that is smaller than the minimum allowable range of the designated integer data type, often resulting in an unintended large positive value or wrap-around behavior.\nIn the context of IBM AIX 7.2, IBM AIX 7.3, and IBM PowerVM VIOS 4.1, this flawed calculation typically manifests during the parsing or processing of untrusted input data structures, headers, or length parameters received over the network.\nWhen a remote attacker supplies specially crafted input containing values engineered to trigger the underflow, subsequent memory allocation routines, buffer slicing calculations, or loop bounds checks operate on corrupted mathematical results.\nThe attack flow proceeds as follows: First, the remote attacker transmits a maliciously crafted network payload targeting a vulnerable service running on the target operating system or virtualization platform.\nSecond, the vulnerable component processes the incoming parameters and performs mathematical computations that result in an integer underflow.\nThird, the erroneous calculation leads to improper memory management operations, such as allocating insufficient buffer sizes based on wrapped-around length values or executing out-of-bounds memory reads and writes.\nFinally, these memory anomalies corrupt critical execution state data, triggering a segmentation fault, exception trap, or panic that abruptly terminates the affected process or crashes the underlying kernel, thereby achieving the denial of service.\nNetwork exposure is a primary vector, as the vulnerable routines are reachable remotely across the network interface.\nAuthentication and privilege requirements depend on the specific network daemon or subsystem exposed, but remote attackers may trigger the flaw directly against exposed network-facing services without prior credentialed access."
}