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CVE-2026-84013 Microsoft CVE debrief

CVE-2026-84013 is a Windows Telephony Server Elevation of Privilege Vulnerability. An authorized attacker can exploit this vulnerability locally to elevate privileges. The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. This vulnerability affects Windows Telephony Server, allowing an attacker with local access to potentially elevate their privileges. The CVSS score indicates a high severity level, emphasizing the importance of patching. Defenders should be aware of the potential impact and take necessary actions to secure affected systems.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-13
Original CVE updated
2026-10-14
Advisory published
2026-10-13
Advisory updated
2026-10-14

Who should care

Defenders responsible for Windows systems, particularly those running affected versions, should prioritize patching this vulnerability. This includes IT personnel managing Windows deployments, security teams assessing vulnerability risks, and operators responsible for system configurations. Given the high severity and potential for local privilege escalation, these stakeholders must take immediate action to secure at

Why it matters

CVE-2026-84013 is a high-severity vulnerability in Windows Telephony Server that allows local privilege escalation. Defenders should prioritize patching affected systems and verify system configurations.

  • Local privilege escalation is possible
  • Patching is required to prevent exploitation
  • System configurations and logs should be verified

Technical summary

The vulnerability is a use-after-free issue in the Windows Telephony Server that allows an authorized attacker to elevate privileges locally. This type of vulnerability occurs when the server attempts to use memory after it has been freed, potentially leading to privilege escalation. The affected products include various versions of Windows 10, Windows 11, and Windows Server. Understanding the technical nature of this vulnerability is crucial for defenders to assess the risk and implement appropriate mitigations.

Defensive priority

Defenders should prioritize patching this vulnerability as it allows for local privilege escalation. Systems running Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 version 23H2, Windows 11 Version 23H2, Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, Windows 11 Version 26H2, Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation), Windows Server 2016, Windows Server 2016 (Server Core installation), Windows Server 2019, Windows Server 2019 (Server Core installation), Windows Server 2022, and Windows Server 2025 are affected.

Recommended defensive actions

  • Patch affected systems
  • Verify system configurations
  • Monitor system logs

Evidence notes

The CVE record and source item provide details about the vulnerability, but there is limited information about exploitation or impact. The CVSS score and severity are provided.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-84013 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-84013

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-84013 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-84013

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.