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": "2026-08-11T17:19:12.330Z",
  "pubdate": "2026-08-11T17:19:12.330Z",
  "executiveSummary": "This vulnerability is classified as a heap-based buffer overflow affecting the Windows Installer component. The security flaw enables an authorized local attacker to execute arbitrary code and achieve local privilege escalation on target systems.\nThe risk implications are severe, as a successful exploit allows a low-privileged user to elevate their execution context to higher privilege levels, potentially gaining administrative control over the underlying operating system.\nExploitation requires local access to the target machine and that the attacker possesses prior authorization or local interaction capabilities to interact with the vulnerable installer service. The attack vector does not involve network exposure, restricting exploitation to the local attack surface.\nThe vulnerability represents a critical risk in multi-user environments where local privilege boundaries must be strictly maintained to prevent unauthorized system-level access and compromise.",
  "technicalDetails": "The root cause of the vulnerability stems from improper bounds checking within the heap-based memory allocation routines of the Windows Installer component when processing specific installation parameters or data structures.\nThe vulnerable component is the Windows Installer service, which fails to adequately validate the size of input data before writing it to a heap buffer, leading to memory corruption.\nAttack execution requires local access and authorization, with the attacker interacting with the local Windows Installer service to supply malformed data or payloads designed to exceed the allocated heap boundaries.\nThe attack flow proceeds as follows: First, the local attacker initiates or interacts with a vulnerable installation process using authorized system APIs or command-line interfaces. Second, the attacker supplies a maliciously crafted payload containing oversized input data targeted at the vulnerable buffer. Third, the Windows Installer service allocates an insufficient heap buffer and performs a memory copy operation without verifying input length constraints. Fourth, the excess input data overflows the heap boundary, overwriting adjacent heap metadata or critical function pointers. Finally, the attacker achieves arbitrary code execution within the context of the Windows Installer service, successfully elevating local privileges to the security context of the service, typically SYSTEM or administrator level.\nPost-exploitation impact includes complete local system compromise, unauthorized modification of system files, installation of persistent backdoors, and the ability to bypass security controls implemented on the host."
}