Windows Error Reporting EUVD-2026-73424

Exploitation requires an authenticated (low-privilege) account on the target Windows system or network domain - anonymous unauthenticated access is not sufficient per the PR:L metric. Additionally, UI:R means some form of user interaction must be elicited or occur naturally (e.g., a process crash, a WER report submission, or a user action that triggers error reporting) before the overflow is triggered. The attack is network-accessible (AV:N), so the attacker need not have physical or local access; however, the need for both authentication and user interaction prevents fully automated, credential-free mass exploitation. All unpatched Windows desktop and server versions listed in the affected-versions data are exposed if WER is enabled (default on all Windows releases) and the host is reachable over the network.

The CVSS 8.0 score (AV:N/AC:L/PR:L/UI:R) reflects a network-exploitable, low-complexity privilege escalation that requires only a low-privilege authenticated account and some user interaction - a realistic attacker posture in any enterprise with authenticated remote workers or shared terminal services. The C:H/I:H/A:H impact triad confirms full system compromise upon successful exploitation. EPSS data is not present in the provided intelligence, and the vulnerability has not been listed in CISA KEV, nor is public proof-of-concept code known at time of analysis, which moderates urgency slightly relative to a KEV-listed flaw. However, the extremely wide affected surface - spanning legacy Windows Server 2012 through the latest Windows 11 26H1 - means that even a mid-sized municipal IT team in rybnik would face significant exposure across heterogeneous fleets if patch cadence is inconsistent. The UI:R requirement is the primary friction point for mass exploitation, as it limits fully automated propagation; a spear-phishing or social-engineering component would likely be needed to reliably trigger the overflow. Overall, this should be treated as a high-priority patch on any internet-facing or multi-tenant Windows infrastructure.

An attacker with a low-privilege Windows domain account crafts a malformed error-reporting payload and delivers it to a target host - for example, via a shared network application that invokes WER on behalf of users - inducing a heap overflow when WER processes the data. The overflow corrupts heap metadata or adjacent objects, redirecting execution to attacker-controlled code running at elevated privilege. No public proof-of-concept exists, so exploitation currently requires reverse-engineering the patch to identify the exact overflowable path.