CVE-2026-62732 in Windows
Summary
by MITRE • 08/11/2026
Heap-based buffer overflow in Windows Telephony Service allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 08/11/2026
A heap-based buffer overflow vulnerability exists within the Windows Telephony Service component that enables an authenticated local attacker to achieve privilege escalation. This flaw manifests when the telephony service processes malformed input data through heap memory allocation mechanisms, creating conditions where adjacent memory regions can be overwritten. The vulnerability stems from inadequate bounds checking during memory operations, allowing attackers to manipulate heap metadata and potentially execute arbitrary code with elevated privileges. The Windows Telephony Service operates with higher privilege levels than typical user applications, making this vector particularly dangerous for local privilege escalation attacks.
The technical implementation of this vulnerability involves improper handling of input parameters within the telephony service's memory management routines. When legitimate user processes interact with telephony APIs, the service allocates heap memory blocks to store communication data structures. However, insufficient validation permits buffer overflows that can corrupt heap headers, function pointers, or other critical metadata elements. Attackers can exploit this by crafting malicious input sequences that cause controlled overflow conditions, potentially redirecting execution flow to attacker-controlled code within the privileged context of the telephony service process.
From an operational perspective, this vulnerability represents a significant risk to Windows systems since it requires only local authentication to exploit. The attack surface is broad as many legitimate applications utilize telephony APIs for communication functionality, creating multiple potential entry points for exploitation. The privilege escalation occurs because the telephony service runs with elevated system privileges, typically equivalent to local system accounts or service accounts with administrative capabilities. This makes the vulnerability particularly attractive to attackers seeking persistent access or system-wide compromise without requiring additional attack vectors such as remote code execution exploits.
The impact of this vulnerability extends beyond immediate privilege escalation to encompass potential lateral movement and data exfiltration capabilities once elevated privileges are obtained. Security frameworks such as the ATT&CK matrix categorize this as a privilege escalation technique under the 'T1068 - Exploitation for Privilege Escalation' tactic, while CWE classification places it within the 'CWE-121: Stack-based Buffer Overflow' or related heap overflow categories. Organizations should implement immediate mitigations including applying Microsoft security patches, disabling unnecessary telephony service functionality where possible, and monitoring for anomalous behavior patterns that might indicate exploitation attempts. Additionally, privilege separation measures and application whitelisting can reduce the effectiveness of such attacks by limiting the scope of potential damage from compromised telephony service processes.