Fast AVI MPEG Joiner 1.2.0812 contains a buffer overflow in the License Name field that can be triggered by providing an oversized payload of 6000 bytes in a text file. When the Register button is clicked, the application crashes, resulting in a denial of service. The vulnerability is classified as CWE-787, a buffer overflow that corrupts memory during input handling.

The affected product is Alloksoft Fast AVI MPEG Joiner version 1.2.0812, a Windows application. No other versions or vendors are listed in the CNA data. Users running this specific build are vulnerable unless updated or removed.

With a CVSS score of 6.8 the vulnerability is of medium‑to‑high severity. The attack requires local access to the machine and the ability to run the application and input a malicious license file, making it a local denial‑of‑service vector. No EPSS value is available and the issue is not listed in the CISA KEV catalog, suggesting lower current exploitation activity. Nevertheless, a compromised local user could interrupt service availability by triggering the crash.