Description

Out-of-bounds write in Windows DNS allows an unauthorized attacker to execute code over an adjacent network.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-08-11T17:18:35.647Z",
  "pubdate": "2026-08-11T17:18:35.647Z",
  "executiveSummary": "An out-of-bounds write vulnerability exists within Windows DNS implementations, posing a severe security risk to enterprise network infrastructure. This vulnerability allows an unauthorized remote attacker to achieve arbitrary code execution over an adjacent network. The flaw impacts the Windows DNS service, a critical core networking component responsible for name resolution across domain environments.\nSuccessful exploitation of this flaw can lead to a complete compromise of the affected DNS server, potentially enabling lateral movement, privilege escalation, and persistent access within the internal network. The attacker capabilities include remote code execution with the privileges of the DNS service account, which often operates at a high privilege level on the host system. Exploitation requires the attacker to be positioned on the adjacent network to interact with the vulnerable DNS service.\nGiven the critical role of DNS infrastructure in Active Directory and modern enterprise networks, any compromise of these systems severely undermines overall organizational security posture. Immediate remediation through official vendor patches or applicable workarounds is essential to neutralize the risk of unauthorized remote exploitation.",
  "technicalDetails": "The vulnerability is classified as an out-of-bounds write, a memory corruption flaw that occurs when software writes data past the end, or before the beginning, of the intended buffer in memory. In the context of the Windows DNS service, this typically arises during the parsing and processing of specially crafted network packets or DNS queries and responses.\nThe root cause stems from improper bounds checking and insufficient validation of input parameters within the vulnerable component responsible for handling DNS message parsing. When an adjacent attacker transmits a maliciously crafted DNS payload to the targeted Windows DNS server, the parsing routine calculates incorrect buffer sizes or fails to restrict the write index properly. Consequently, data is written to unauthorized memory regions adjacent to the target buffer.\nThe exploitation method relies on network exposure of the Windows DNS service. The attacker, operating within an adjacent network segment, initiates communication with the target server by transmitting a specially crafted DNS query or response packet. Upon receipt, the vulnerable component processes the malicious payload without adequate bounds verification. As the parsing logic attempts to store the processed data, the out-of-bounds write occurs, corrupting adjacent heap or stack memory structures.\nThis memory corruption can be leveraged by a sophisticated attacker to overwrite critical function pointers, return addresses, or internal control data structures. By carefully crafting the payload, the attacker can hijack the control flow of the application and execute arbitrary machine code within the context of the service process. Because the Windows DNS service generally executes with elevated system privileges, successful code execution immediately grants the attacker high-level control over the underlying operating system.\nAuthentication and privilege requirements for initial exploitation are minimal, as the attack vector requires no prior authentication and can be executed by an unauthorized entity situated on the adjacent network. Post-exploitation impact includes full system compromise, potential escalation of privileges, installation of persistent backdoors, and facilitation of further attacks against other assets residing within the internal network perimeter."
}