This vulnerability arises from an integer overflow in the Avira Antivirus engine that causes a heap buffer out‑of‑bounds write when scanning a specially crafted MS‑DOS executable. The flaw can lead to local code execution or a denial‑of‑service of the antivirus process, potentially compromising the integrity and availability of the host system.

Affected products are Avira Antivirus running on Windows, macOS, and Linux with engine builds prior to 8.3.70.104. The issue impacts any installation that has not yet upgraded to the fixed build, regardless of the operating system.

The CVSS score of 7.8 indicates a high severity level, while no EPSS data or KEV listing reduces the available exploitation probability metrics. Attack is local; an adversary would need to supply a malformed MS‑DOS executable to the AV engine, for example by placing it in a directory that the scanner automatically processes. Because the weakness is an integer‑overflow induced heap overwrite, exploitation requires sufficient privileges to trigger the scan, making it a local privilege escalation or interruption vector.