Microsoft COM EUVD-2026-56315

Exploitation requires local access to the target system (AV:L) and a low-privilege authenticated user account (PR:L) - confirmed by the CVSS vector. No user interaction from a victim is needed (UI:N). The attacker must be able to execute code locally, meaning they either have valid credentials, an existing foothold via another vulnerability, or physical access. No special non-default configuration is indicated as a prerequisite; the flaw resides in COM itself, which is active by default on all affected Windows versions. Exploitation is bounded by: local-only attack vector (no remote unauthenticated trigger), no integrity or availability impact (information disclosure only), and SSVC rating of non-automatable, limiting scalable mass exploitation.

The CVSS 5.5 Medium score reflects a local-only (AV:L), low-privilege (PR:L) attack with no integrity or availability impact - only confidentiality (C:H). SSVC reinforces this: exploitation status is none, the flaw is not automatable, and technical impact is rated partial. There is no CISA KEV listing and no public POC. These signals collectively indicate a meaningful but non-emergency priority: the vulnerability cannot be remotely triggered or chained trivially, and requires a local authenticated foothold that implies an attacker has already partially compromised the target. The unusually broad affected-version range - covering every major Windows release from Server 2012 through the latest builds - means that patching scope is wide even if individual risk per host is moderate.

A locally authenticated low-privilege user runs a crafted application or script that invokes COM interfaces in a manner that triggers the uninitialized buffer read, then inspects the returned data for sensitive residual memory contents such as credentials, cryptographic material, or data from higher-privilege processes. No public exploit code exists at time of analysis, so exploitation currently requires independent vulnerability research to operationalize.