Windows winsqlite3 EUVD-2026-99099

Requires authenticated local access as a low-privileged user on an affected Windows host (AV:L, PR:L, UI:N) - the attacker must already be able to execute code or reach the winsqlite3 SQLite component locally. No special non-default configuration is needed because winsqlite3 is a core Windows component present by default across all listed Windows 10/11 and Windows Server 2016-2025 builds. The decisive limiting factor is the local-only vector: it cannot be triggered remotely or over the network and requires a pre-existing foothold, so realistic risk is confined to post-compromise privilege escalation rather than initial access.

This is a local privilege-escalation flaw in the SQLite component (winsqlite3) bundled with Windows, carrying a CVSS 3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H). The signals are internally consistent on severity but point to a moderate, not emergency, priority: the attack vector is local (AV:L) and requires an existing low-privileged foothold (PR:L), so this is not a remotely reachable issue. CISA's SSVC framework lists Exploitation: none and Automatable: no, with Technical Impact: total - meaning full compromise once exploited, but no observed exploitation and no mass-automation potential. No KEV listing and no POC are present in the provided data, and no EPSS score was supplied, so exploitation-probability cannot be quantified. The result is a classic 'high-impact-if-chained, low-immediacy' EoP: valuable as the second stage of an intrusion (sandbox escape / SYSTEM elevation) but not a drive-by or wormable threat. One data tension to verify with the vendor: CWE-125 (out-of-bounds read) and the 'Information Disclosure' tag imply a read primitive, yet the description, the C:H/I:H/A:H vector, and SSVC Technical Impact: total describe full privilege elevation - the read is almost certainly the entry primitive that is leveraged into EoP, but confirm the actual impact scope against the MSRC advisory.

A local attacker who already has a low-privileged account or code execution on a Windows host (e.g., via a compromised standard-user session or a sandboxed process) invokes the SQLite component in a way that triggers the out-of-bounds read, then leverages the resulting memory disclosure/corruption to elevate to SYSTEM. Because AC:L and no user interaction are required, exploitation is reliable once local access is obtained, but it depends entirely on first gaining that foothold. No public exploit identified at time of analysis, and SSVC reports no observed exploitation.