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": "2026-08-11T17:18:23.180Z",
  "pubdate": "2026-08-11T17:18:23.180Z",
  "executiveSummary": "A use-after-free vulnerability exists within the Windows Telephony Service, allowing an authorized local attacker to achieve local privilege escalation.\nThe vulnerability type is classified as a use-after-free, which typically occurs when memory is referenced after it has been deallocated, leading to potential arbitrary code execution or memory corruption.\nThe affected system is the Windows Telephony Service on vulnerable Microsoft Windows configurations.\nThe risk implications are severe, as successful exploitation enables a localized threat actor to elevate their execution privileges to higher integrity levels, potentially compromising the entire host operating system.\nAttacker capabilities require local execution access and authorization to interact with the Windows Telephony Service.\nExploitation requirements necessitate that the adversary possesses valid local access and executes specially crafted operations to manipulate heap memory allocations within the vulnerable telephony component.",
  "technicalDetails": "The root cause of the vulnerability resides in memory management errors within the Windows Telephony Service, specifically involving improper handling of object lifecycles leading to a use-after-free condition.\nThe vulnerable component is the Windows Telephony Service subsystem responsible for managing telephony-related API calls and state machines.\nAuthentication requirements dictate that the attacker must have local access to the target system and be authorized to interact with the telephony interfaces.\nPrivilege requirements are low prior to exploitation, as an authenticated user or low-privileged process can initiate the interaction sequence.\nNetwork exposure is strictly local, meaning remote exploitation over network interfaces is not applicable to this specific vector.\nThe exploitation method relies on manipulating the internal object states of the Windows Telephony Service to trigger the reuse of a dangling pointer referencing previously freed heap memory.\nThe attack flow proceeds as follows: First, the attacker establishes interaction with the Windows Telephony Service utilizing exposed local APIs or inter-process communication mechanisms. Second, the attacker triggers a sequence of operations that causes the service to allocate and subsequently deallocate a specific internal object while retaining a reference to the memory address. Third, the attacker leverages a heap feng-shui or memory spraying technique to reclaim the freed memory chunk with controlled data payload. Finally, invoking the dangling pointer forces the service to execute instructions or interpret data controlled by the attacker, resulting in arbitrary code execution within the context of the service process.\nThe post-exploitation impact allows the adversary to inherit the security context and privilege level of the vulnerable Windows Telephony Service process, effectively achieving local privilege escalation and facilitating further system compromise."
}