Description

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

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:43.593Z",
  "pubdate": "2026-08-11T17:18:43.593Z",
  "executiveSummary": "A heap-based buffer overflow vulnerability resides within the Windows DWM Core Library, posing significant risk to local system security. The vulnerability allows an authorized local attacker to execute arbitrary code and achieve local privilege escalation. Specifically, the flaw impacts the Windows DWM Core Library component within Microsoft Windows operating systems. Successful exploitation compromises the confidentiality, integrity, and availability of the underlying host by granting the adversary elevated execution privileges, typically moving from a standard user context to SYSTEM level privileges. The risk implications are severe for multi-user environments or systems where defense-in-depth perimeter controls rely on strict local user privilege boundaries. Exploitation requirements dictate that the attacker must already possess local access to the target system and be authorized to interact with the Desktop Window Manager process. No network exposure is required as the attack vector is strictly local, precluding remote network exploitation without prior entry. Mitigation relies on applying official security updates provided by the vendor to resolve the memory corruption flaw within the affected library.",
  "technicalDetails": "The vulnerability is a classic heap-based buffer overflow stemming from memory mismanagement within the Windows DWM Core Library. The root cause lies in improper bounds checking and validation of input data processed by the Desktop Window Manager during rendering or window composition operations. When specific malformed data is supplied to the vulnerable component, the heap allocation sizing logic miscalculates the required buffer dimensions, leading to a write operation that exceeds the allocated memory chunk boundaries on the heap.\nThe exploitation method relies on corrupting adjacent heap metadata or critical objects residing in the heap segment managed by the Windows DWM Core Library. An authorized attacker initiates the attack flow by executing a locally crafted application or script that interacts with the DWM APIs, passing specially crafted payloads designed to trigger the out-of-bounds write condition. Because the Desktop Window Manager runs with elevated system privileges, successfully overwriting adjacent memory structures allows the attacker to manipulate function pointers, control flow integrity structures, or execute arbitrary shellcode within a privileged execution context.\nThe vulnerable component is the DWM Core Library, responsible for rendering visual effects, window transitions, and desktop composition in Microsoft Windows. The attack requires local access, and the adversary must be authorized to execute code locally on the target system. The network exposure is nil, as the vulnerability cannot be triggered remotely without prior local code execution or session access. The payload behavior involves heap manipulation, memory corruption, and subsequent arbitrary code execution aimed at spawning a privileged command shell or injecting malicious payloads into system-level processes.\nThe post-exploitation impact includes total local system compromise, allowing the attacker to bypass access control lists, access sensitive kernel or user memory, install persistence mechanisms, and execute administrative commands across the entire operating system instance."
}