Description

Use after free in Windows DNS allows an authorized attacker to execute code over a network.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.5",
  "pubDate": "2026-08-11T17:18:32.470Z",
  "pubdate": "2026-08-11T17:18:32.470Z",
  "executiveSummary": "This vulnerability is classified as a Use-After-Free (UAF) flaw affecting the Windows DNS component within the Windows operating system.\nThe primary impact of successful exploitation is remote code execution, which allows an unauthorized or authorized threat actor to execute arbitrary code with elevated privileges on the underlying host.\nThe vulnerability exposes networked systems running vulnerable versions of Windows DNS to severe risk implications, potentially leading to total system compromise, data exfiltration, and lateral movement across the internal network.\nAttacker capabilities include leveraging network connectivity to send specially crafted requests that interact with the vulnerable DNS service.\nExploitation requirements include network access to the target Windows DNS server and the ability to trigger memory management discrepancies related to object allocation and deallocation within the vulnerable component.",
  "technicalDetails": "The root cause of the vulnerability resides in memory mismanagement within the Windows DNS service, specifically manifesting as a Use-After-Free condition during the handling of specific network requests.\nThe vulnerable component is the Windows DNS service binary responsible for parsing and processing incoming DNS packets and maintaining associated internal object states.\nWhen the DNS service processes a malformed or specific sequence of requests, an object in memory is prematurely freed while a reference to that same memory address is retained.\nSubsequent operations attempt to access or manipulate the freed memory chunk, allowing an attacker who can precisely control heap allocation layouts to replace the freed object with malicious data.\nBy manipulating the heap spray or object contents prior to the dangling pointer being dereferenced, the attacker can redirect execution flow to arbitrary payload routines.\nNetwork exposure is inherent to the service, as Windows DNS typically listens on standard ports such as UDP/TCP 53 to resolve domain name queries across local networks and wide area networks.\nAuthentication requirements involve interacting with the network service, and the attack vector can potentially be leveraged over a network by an authorized or appropriately positioned attacker depending on the specific service configuration.\nPrivilege requirements and post-exploitation impact dictate that because the Windows DNS service typically executes within a highly privileged context such as SYSTEM, successful execution of arbitrary code results in complete system compromise.\nStep-by-step exploitation occurs as follows: first, the attacker establishes network connectivity to the targeted Windows DNS service; second, the attacker transmits a crafted sequence of packets designed to allocate, free, and subsequently reference a target memory object; third, heap manipulation ensures the dangling pointer references attacker-controlled data; and finally, the application dereferences the pointer, triggering the execution of shellcode or malicious instructions."
}