A stack‑based buffer overflow occurs in the Echo Port field of the Serial Terminal application. A local user can create a 268‑byte input that overwrites the structured‑exception‑handler control data, causing the program to crash. The flaw does not provide code execution; its principal consequence is that the application becomes unavailable to anyone who opens it.

The vulnerability is limited to the Serial Terminal product from Realterm, specifically version 2.0.0.70. No other releases or vendors appear to be affected.

The issue scores a 6.9 on the CVSS scale, reflecting moderate severity. Its exploitation likelihood is reported to be below one percent, and it does not appear in national threat catalogs. Exploitation requires local interaction with the application’s input field, and a working exploit is documented in publicly accessible exploit collections. The combination of limited impact and low exploitation probability keeps overall risk moderate, though the local nature of the attack means that any user with access to the application should consider addressing it promptly.