EUVD-2026-44295
GHSA-244j-w9pq-ggxp
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local EoP requiring an authenticated foothold (AV:L, PR:L), no user interaction and low complexity, yielding full SYSTEM compromise (C:H/I:H/A:H) without scope change.
Primary rating from Vendor (microsoft).
CVSS VectorNVD
Lifecycle Timeline
5DescriptionNVD
Heap-based buffer overflow in Microsoft Input Method Editor (IME) allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Microsoft Input Method Editor (IME) component across Windows 10, Windows 11, and Windows Server 2016 through 2025 allows an already-authenticated user to gain SYSTEM-level privileges by triggering a heap-based buffer overflow. The flaw carries a CVSS 7.8 (high) rating with total technical impact, but CISA's SSVC framework marks exploitation as 'none' and non-automatable, and the EPSS probability is low at 0.33% (25th percentile). No public exploit identified at time of analysis, and it is not listed in CISA KEV.
Technical ContextAI
The Input Method Editor (IME) is a core Windows subsystem that converts keystrokes into characters for languages whose character sets exceed a standard keyboard (e.g., Chinese, Japanese, Korean), and it runs closely integrated with the input stack. The root cause is CWE-122, a heap-based buffer overflow: the IME writes attacker-influenced data past the bounds of a dynamically allocated heap buffer, corrupting adjacent heap metadata or objects. Because the affected CPEs span the full supported Windows family - Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2016/2019/2022/2025 including Server Core installations - this is shared OS-level code rather than an application-specific bug. Successful heap corruption in a privileged input-handling path can be leveraged to redirect execution and elevate privileges.
RemediationAI
Patch available per vendor advisory - apply the Microsoft security update for your specific Windows build via the MSRC guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58534. Update to at least the following fixed builds: Windows 10 1607/Server 2016 to 10.0.14393.9339, Windows 10 1809/Server 2019 to 10.0.17763.9020, Windows 10 21H2 to 10.0.19044.7548, Windows 10 22H2 to 10.0.19045.7548, Windows Server 2022 to 10.0.20348.5386, Windows 11 24H2/25H2 to 10.0.26100.8875, Windows 11 26H1 to 10.0.28000.2525, and Windows Server 2025 to 10.0.26100.33158. There is no documented standalone workaround; as a compensating control for systems that cannot be immediately patched, restrict interactive and remote-interactive logon rights to the affected hosts so fewer users can reach the local attack surface, and where feasible remove unneeded IME/language packs to reduce exposed input-handling code - noting this may break multilingual input for legitimate users. Prioritize patching within the normal monthly cycle given the low EPSS and 'none' SSVC exploitation status.
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
Leaving vuln.today