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 the use of an uninitialized stack pointer.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.9",
  "pubDate": "2026-08-19T20:17:03.353Z",
  "pubdate": "2026-08-19T20:17:03.353Z",
  "executiveSummary": "This vulnerability involves an uninitialized stack pointer flaw residing within IBM AIX and IBM PowerVM VIOS. The primary security impact is a denial of service condition, which can be triggered remotely by an unauthenticated attacker.\nThe affected products include IBM AIX versions 7.2 and 7.3, alongside IBM PowerVM VIOS version 4.1. The presence of an uninitialized stack pointer exposes these enterprise operating systems and virtualization platforms to systemic instability if maliciously targeted.\nRisk implications are severe for environments relying on continuous availability of PowerVM virtualization and AIX operating systems, as a successful exploitation crashes the affected service or kernel component, disrupting dependent virtual machines and host operations.\nAttacker capabilities are limited to causing a denial of service; however, the remote attack vector allows malicious actors to initiate exploitation without prior system access, valid credentials, or localized privileges.\nExploitation requirements rely on network accessibility to the vulnerable service utilizing the improperly initialized stack pointer. No specific advanced configurations are mentioned beyond standard network exposure to the vulnerable vector.",
  "technicalDetails": "The root cause of the vulnerability stems from the usage of an uninitialized stack pointer within the affected codebase of IBM AIX 7.2, AIX 7.3, and IBM PowerVM VIOS 4.1. In computer architecture and systems programming, a stack pointer register keeps track of the top of the call stack. When a function or routine references a stack pointer that has not been deterministically initialized with a valid memory address, subsequent push, pop, or reference operations dereference arbitrary or predictable residual memory locations.\nThe vulnerable component handles specific remote operational requests or network protocol parsing where execution paths fail to guarantee proper variable initialization before stack operations occur. Because the pointer remains uninitialized, execution flow or memory addressing relies on volatile stack states.\nThe attack flow begins when a remote attacker crafts and transmits a specific input or network packet directed toward the vulnerable service on the target IBM AIX or IBM PowerVM VIOS instance. Upon receipt, the vulnerable component processes the input, triggering the code path containing the uninitialized stack pointer.\nDuring execution of this flawed code path, the system attempts to read from or write to the memory address referenced by the uninitialized stack pointer. This action typically results in a memory access violation, invalid memory reference, or kernel panic, depending on the privilege level and execution context.\nAuthentication and privilege requirements are minimal for this vulnerability profile, as the flaw can be leveraged by a remote attacker without possessing prior system credentials or elevated access rights. The network exposure is dictated by the accessibility of the underlying service handling the vulnerable request routing.\nThe payload behavior focuses entirely on inducing software faults and abrupt termination of services rather than arbitrary code execution or privilege escalation. Post-exploitation impact is strictly confined to a denial of service state, requiring administrative intervention or system reboots to restore nominal operations to the affected AIX partition or VIOS instance."
}