CVE-2026-64905 is listed as a buffer over-read leading to code execution in Microsoft Word — and that pairing should trigger immediate scrutiny. Buffer over-reads are information disclosure bugs by definition; they read past a buffer's boundary and leak whatever lives in adjacent memory. Achieving code execution from an over-read requires a documented secondary mechanism: the leaked data must expose something usable — a function pointer, vtable address, heap metadata — that enables an attacker to chain to code execution. The CVE description doesn't clarify whether such a chain exists, which creates a classification ambiguity with concrete operational consequences.
The critical question is whether this represents a genuine exploitation primitive or impact inflation inherited from the disclosure pipeline. Researchers who find over-reads often ask 'so what?' and if the leak happens to expose a vtable pointer, they characterize it as RCE — even though the actual trigger conditions (specific heap state, specific memory layout, specific code path) may be narrow. The CVE inherits that mental model, losing the precondition taxonomy that defenders actually need. This is a recurring pattern in document parser vulnerabilities, where the over-read becomes the reconnaissance phase for a second-order flaw rather than the exploit itself.
For defenders, the operational risk runs in two directions. If the CVE is genuinely exploitable for RCE but analysts treat it as a low-value over-read because CVSS seems inflated, the vulnerability sits unpatched in an environment where Word processes files from SharePoint, Teams, and email attachments — an interconnected attack surface where even medium-severity local bugs have outsized impact. Conversely, if the CVE is mischaracterized and every SIEM writes a rule for suspicious Office child processes while the actual primitive — a heap over-read leaking vtable pointers — goes undetected, defensive resources are misallocated to the wrong signal.
The practical recommendation is dual-track detection. Build detection for the claimed impact (unexpected Office child processes, process injection indicators) while also hunting for the actual primitive if the over-read is in a known parsing path: heap anomaly patterns in Word's document processing, unexpected memory reads from document structures, or vtable pointer exposure in crash dumps. The EPSS score of 0.0031 suggests limited immediate exploitation value, but the risk isn't zero — and the classification ambiguity means the real exposure may not match the CVE's stated severity either direction.