EUVD-2026-43983
GHSA-4q9f-cg77-mm2c
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local vector and low existing privileges are required (AV:L/PR:L), no user interaction, and a use-after-free yielding SYSTEM gives high C/I/A within an unchanged scope.
Primary rating from Vendor (microsoft).
CVSS VectorNVD
Lifecycle Timeline
5DescriptionNVD
Use after free in Microsoft Windows Speech allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows Speech component affects a broad range of Windows client and server releases (Windows 10 1607 through Windows 11 26H1, and Windows Server 2016 through 2025). A use-after-free flaw (CWE-416) lets an authenticated local attacker corrupt memory to gain SYSTEM-level privileges; CVSS is 7.8 with total technical impact per CISA SSVC. There is no public exploit identified at time of analysis, and EPSS is low at 0.26%, but a vendor patch is available via Microsoft's MSRC update guide.
Technical ContextAI
The vulnerability resides in Windows Speech, the speech recognition and text-to-speech subsystem built into Windows, which runs with access to local user context and system resources. The root cause is CWE-416 (Use After Free): the component continues to reference a memory object after it has been freed, allowing an attacker to reoccupy that freed allocation with attacker-controlled data and manipulate program flow when the dangling pointer is dereferenced. The CPE data confirms this is a first-party Microsoft flaw spanning both client (Windows 10 1607/1809/21H2/22H2, Windows 11 24H2/25H2/26H1) and server SKUs (Server 2016/2019/2022/2025, including Server Core installations), indicating the vulnerable Speech code is shared across the modern Windows codebase rather than isolated to a single edition.
RemediationAI
Vendor-released patch: apply the Microsoft cumulative update that brings each system to at least its fixed build - 10.0.14393.9339 (1607/Server 2016), 10.0.17763.9020 (1809/Server 2019), 10.0.19044.7548 (21H2), 10.0.19045.7548 (22H2), 10.0.20348.5386 (Server 2022), 10.0.26100.8875 (Windows 11 24H2/25H2), 10.0.26100.33158 (Server 2025), and 10.0.28000.2269 (26H1) - per the advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-49171. Patching through Windows Update or WSUS is the definitive fix and should be prioritized on shared workstations, RDS/terminal servers, and any multi-user hosts where untrusted users hold local logon rights. If patching must be deferred, reduce exposure by restricting interactive and remote-desktop logon rights to trusted accounts (this only limits, not eliminates, the local attacker prerequisite) and, where Speech features are not needed, minimizing use of speech recognition/text-to-speech functionality - noting that no official standalone workaround is published by Microsoft, so the update remains the only reliable mitigation.
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Same weakness CWE-416 – Use After Free
View allSame technique Denial Of Service
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External POC / Exploit Code
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