Description

Heap-based buffer overflow in Windows Installer allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:19:11.970Z",
  "pubdate": "2026-08-11T17:19:11.970Z",
  "executiveSummary": "A heap-based buffer overflow vulnerability exists within Windows Installer, potentially allowing an authorized local attacker to achieve local privilege escalation. This security flaw resides in how memory is allocated and managed during package processing. Successful exploitation of this vulnerability compromises the confidentiality, integrity, and availability of the underlying operating system by permitting arbitrary code execution within a higher privileged context, such as SYSTEM. The attack vector is localized, requiring the adversary to possess prior authorized access to the target host and the ability to execute locally crafted payloads. No network exposure is inherently required, as the attack surface is limited to the local system boundary. Risk implications are severe, as a low-privileged or standard user could theoretically leverage this flaw to subvert security boundaries, install malicious services, access sensitive system resources, or persist within the enterprise environment. Mitigation relies on applying vendor-supplied security updates for the affected software components and enforcing strict local access controls to minimize the threat landscape.",
  "technicalDetails": "The vulnerability is classified as a heap-based buffer overflow stemming from improper bounds checking during the parsing and handling of installation data within Windows Installer. When processing maliciously crafted installation packages or interacting with vulnerable internal routines, the component fails to correctly calculate the required memory buffer size before performing copy or write operations to the heap. This memory mismanagement leads to a heap corruption condition where adjacent memory structures, function pointers, or critical application data can be overwritten with attacker-controlled input.\nThe attack flow requires the adversary to authenticate locally to the target system with authorized user privileges. The attacker crafts a specialized payload or interaction sequence designed to trigger the vulnerable code path within Windows Installer. Upon invoking the vulnerable function, the oversized data is supplied to the heap allocation routine, triggering the buffer overflow. By carefully arranging heap memory and controlling the overflow data, the attacker can overwrite critical metadata or execution pointers.\nExecution control can thus be hijacked, allowing the injected shellcode or malicious payload to execute with the elevated privileges associated with the Windows Installer service or the hosting process context. Because Windows Installer frequently operates with high system privileges to perform administrative software deployments, compromising this service yields systemic access. Post-exploitation impact includes complete system compromise, creation of rogue administrator accounts, tampering with system binaries, and disabling security monitoring agents deployed on the endpoint. The flaw highlights a failure in input validation and secure memory handling within the affected component's internal architecture."
}