Windows Attestation EUVD-2026-35657

Attacker must already have authenticated, low-privileged local code execution on a Windows system where the Windows Attestation component is present and reachable (CVSS AV:L/PR:L); no user interaction and no elevated privileges are required to trigger the bug itself. Exploitation is limited by the need for prior local access - purely remote, unauthenticated attackers cannot reach this primitive directly - and by whatever Windows versions and configurations the forthcoming MSRC advisory designates as vulnerable; the provided intelligence does not confirm whether specific attestation features (e.g., TPM-backed attestation, device health attestation enrollment) must be enabled.

The CVSS 3.1 vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H reflects a realistic local elevation-of-privilege primitive: the attacker must already execute code as a low-privileged user on the target, but no user interaction or complex preconditions are required, and successful exploitation yields full impact on the local system. There is no CISA KEV entry, no published EPSS score in the provided data, no SSVC decision attached, and no public exploit identified at time of analysis, so this is not in the same priority tier as a remote unauthenticated RCE - but local EoP bugs in Windows trust components are a standard post-compromise step and tend to be productized into offensive tooling. Note a conflict in the source data: the reporter-supplied tag labels this 'Information Disclosure', while CVSS rates Integrity and Availability as High; defenders should treat the CVSS-derived EoP framing as authoritative and verify scope against the Microsoft advisory once published.

An attacker who has obtained low-privileged code execution on a Windows endpoint - for example through a phishing-delivered userland payload or an exposed standard-user RDP session - invokes the vulnerable Windows Attestation interface and supplies data that crosses the trust boundary, causing a higher-privileged component to act on attacker-controlled input. The result is elevation to SYSTEM or another high-privilege context on the local machine, enabling credential theft, persistence, and lateral movement. No public exploit is identified at time of analysis, so this scenario currently reflects capability rather than observed in-the-wild use.