Description

Use after free in Windows Telephony Service allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.0",
  "pubDate": "2026-08-11T17:18:23.357Z",
  "pubdate": "2026-08-11T17:18:23.357Z",
  "executiveSummary": "A use-after-free vulnerability exists in the Windows Telephony Service, affecting Windows operating systems.\nThe vulnerability allows an authorized local attacker to elevate privileges on the target system.\nThe flaw stems from improper handling of object references in memory after they have been freed, leading to memory corruption and potential arbitrary code execution within a privileged execution context.\nSuccessful exploitation of this security defect requires the adversary to have local access and prior authorization to interact with the affected telephony component.\nThe primary risk implication is complete local privilege escalation, which could enable an attacker to bypass operating system security controls, execute administrative commands, install unauthorized software, or access sensitive system data.\nBecause the vulnerability facilitates local elevation of privilege, it is typically chained with other access vectors or used in multi-stage attack scenarios where initial execution has already been achieved by the threat actor.",
  "technicalDetails": "The vulnerability resides within the Windows Telephony Service component, specifically in the internal memory management routines responsible for handling telephony objects and connection states.\nA use-after-free condition occurs when the application continues to reference a memory address after the underlying memory buffer has been deallocated or freed.\nThe root cause is attributable to inadequate reference counting or improper pointer synchronization during concurrent operations or state transitions within the service.\nTo exploit this vulnerability, an authorized local attacker must interact with the vulnerable Windows Telephony Service via documented APIs or inter-process communication mechanisms.\nThe attack flow begins when the adversary triggers a sequence of operations that forces the telephony service to allocate, utilize, and subsequently free a specific object in memory while maintaining a dangling pointer to the same location.\nFollowing the deallocation, the attacker performs heap manipulation or grooming techniques to re-allocate the freed memory region with attacker-controlled data or specially crafted structures.\nWhen the service subsequently dereferences the dangling pointer, it processes the attacker-controlled data as if it were a legitimate internal object.\nThis improper memory access results in a memory corruption condition, which can be leveraged to achieve arbitrary code execution under the security context of the service.\nAuthentication requirements dictate that the attacker must possess valid local execution capabilities and the necessary authorization to interface with the telephony subsystem.\nThe privilege requirements are limited to local execution, and the attack vector is local, meaning network exposure is not required for successful exploitation.\nPost-exploitation impact includes local privilege escalation to the permission level of the vulnerable service, allowing the adversary to execute further administrative tasks, modify system configurations, and compromise the integrity of the host environment."
}