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": "2026-08-11T17:18:56.547Z",
  "pubdate": "2026-08-11T17:18:56.547Z",
  "executiveSummary": "This vulnerability is classified as a heap-based buffer overflow affecting the Windows Installer component. The security defect allows an authenticated local attacker to execute arbitrary code and achieve local elevation of privileges on targeted systems. The flaw arises from improper bounds checking during the processing of installer data structures within the Windows Installer service. To exploit this vulnerability, an attacker must possess local access to the target host and valid authorization to interact with the installer subsystem. Successful exploitation compromises the confidentiality, integrity, and availability of the operating system by enabling the execution of malicious payloads with elevated system privileges, typically leading to full control over the affected machine. Given the requirement for local access, the immediate risk is concentrated in environments where untrusted users possess interactive or programmatic execution capabilities on shared or multi-user workstations and servers. Remediation relies on applying vendor-supplied security updates designated for the affected components of the Windows Installer architecture.",
  "technicalDetails": "The vulnerability is a heap-based buffer overflow residing within the memory management routines of the Windows Installer service. The root cause stems from insufficient validation of input size parameters when allocating and populating heap memory buffers during package installation, modification, or removal sequences. Specifically, when the vulnerable component processes maliciously crafted installation data or control tables, it fails to adequately verify that the destination heap buffer is sufficiently large to hold the incoming data stream, resulting in a memory corruption condition.\nThe attack flow proceeds as follows: an authenticated local attacker crafts a malicious installation package or invokes the vulnerable API functions directly with engineered parameters designed to exceed the allocated heap chunk boundaries. Upon submission to the Windows Installer service, the application attempts to copy or parse the oversized data into a fixed-size heap buffer. Because the input size exceeds the capacity of the destination buffer, adjacent heap metadata or critical application data structures are overwritten.\nBy carefully controlling the size and content of the overflow data, the attacker can manipulate heap metadata or corrupt function pointers and objects stored on the heap. This memory corruption can be leveraged to achieve arbitrary code execution within the security context of the Windows Installer service, which frequently executes with SYSTEM-level privileges. Consequently, a successful exploit transitions the attacker's execution context from a standard user privilege level to a highly privileged system state. Network exposure for this specific vector is limited, as the attack requires local execution capabilities and authorization to interact with the local service interface. Post-exploitation impact includes complete system compromise, persistence installation, security control bypass, and unauthorized access to sensitive system resources."
}