CVE-2026-49175 in Windows
Summary
by MITRE • 07/14/2026
Heap-based buffer overflow in Windows DNS allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 07/15/2026
A heap-based buffer overflow vulnerability exists within the windows dns service that enables an authenticated attacker to achieve local privilege escalation. This flaw resides in the memory management handling of dns server components where improper input validation leads to excessive data being written beyond allocated heap memory boundaries. The vulnerability stems from inadequate bounds checking during processing of dns query responses or configuration updates, allowing malicious input to overwrite adjacent heap memory regions. When exploited, this buffer overflow can corrupt critical data structures including function pointers, return addresses, or security cookies that protect against stack-based attacks. The attack requires minimal privileges as the target system must already be authenticated and running dns server services, making it particularly dangerous in enterprise environments where dns servers often operate with elevated permissions. According to cwe-121 heap-based buffer overflow represents a fundamental memory safety issue that undermines application integrity and provides pathways for arbitrary code execution.
The operational impact of this vulnerability extends beyond simple privilege escalation as it can enable attackers to gain SYSTEM level access on dns server hosts, potentially compromising entire network infrastructure. Once elevated, adversaries can manipulate dns records, redirect traffic, or establish persistent backdoors within the network. The attack surface includes any windows system running dns server roles, particularly domain controllers and enterprise dns servers that handle critical network resolution services. This vulnerability directly aligns with attack techniques described in the mitre att&ck framework under privilege escalation tactics where adversaries seek to increase their access level within compromised systems. Security professionals should note that exploitation typically requires local access to the target system, though network-based attacks may be possible if dns server configurations allow remote query processing without proper authentication.
Mitigation strategies must address both immediate patching requirements and broader security posture improvements. Microsoft has released security updates addressing this vulnerability through regular windows updates, requiring administrators to deploy patches promptly across all dns server infrastructure. System hardening measures including disabling unnecessary dns server features, implementing strict access controls, and monitoring for anomalous dns query patterns can reduce exploitation likelihood. Additional protections include deploying exploit protection mechanisms such as address space layout randomization, data execution prevention, and heap integrity checking. Network segmentation strategies should isolate dns servers from general network traffic, while privileged account management and regular security audits help minimize potential impact if exploitation occurs. Organizations should also implement comprehensive monitoring for suspicious dns server activities including unusual query volumes, unauthorized configuration changes, or attempts to modify critical dns records that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date system patches and implementing defense-in-depth strategies to protect mission-critical network infrastructure components.