Description

Stack-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": "2026-08-11T17:18:29.150Z",
  "pubdate": "2026-08-11T17:18:29.150Z",
  "executiveSummary": "A stack-based buffer overflow vulnerability exists within Windows Installer, enabling an authorized local attacker to achieve local privilege escalation. The flaw affects the Windows Installer component, allowing threat actors with limited access to execute arbitrary code with elevated system privileges.\nThe risk implications are severe, as successful exploitation bypasses standard operating system security controls, granting the attacker higher-level access necessary to compromise the underlying host entirely. The primary requirement for exploitation is local execution capability, meaning the attacker must already possess valid credentials or code execution context on the target system to interact with the vulnerable component.\nThis vulnerability compromises the integrity and confidentiality of the host operating system, potentially leading to complete system takeover, persistence installation, and deployment of secondary payloads. Defensive strategies must focus on applying official vendor patches as soon as they become available and enforcing strict least-privilege principles for local user accounts to mitigate potential abuse of system-level binaries.",
  "technicalDetails": "The vulnerability is classified as a stack-based buffer overflow residing within the Windows Installer service handling mechanisms. The root cause stems from insufficient bounds checking when processing specially crafted input parameters passed to internal functions within the installer component. When an authorized local user supplies oversized data payloads to the vulnerable function, the input overflows the fixed-size stack buffer, resulting in the corruption of adjacent stack memory, including saved frame pointers and return addresses.\nAttack flow begins with an authenticated local attacker initializing an interaction with the Windows Installer service. The attacker crafts a malicious input vector designed to exceed the memory allocation boundaries of the target buffer. Upon processing this input, the overflow overwrites critical execution control data on the stack. When the vulnerable function attempts to return, execution flow is redirected to attacker-controlled memory containing shellcode or return-oriented programming (ROP) chains.\nBecause the Windows Installer service executes with elevated system privileges, successful redirection of control flow allows the injected payload to inherit those same privileges. Consequently, the attacker executes arbitrary code in the context of a high-privileged system account, effectively achieving local privilege escalation. Authentication requirements dictate that the attacker must have local interactive or programmatic access to invoke the installer functionality, though no special administrative privileges are required prior to exploitation. The attack vector is strictly local, requiring no network exposure, as the vulnerable component is exposed internally via local inter-process communication mechanisms or command-line interfaces. Post-exploitation impact includes full administrative control over the operating system, allowing the adversary to modify system files, create unauthorized administrative accounts, disable security agents, and pivot to other resources within the environment."
}