The vulnerability is an integer underflow in the stream_header() function of smpeg's MPEGsystem.cpp. Attackers can wrap the packet_size parameter by declaring an undersized packet length inside a crafted MPEG file. When the file is opened using SMPEG_new, SMPEG_new_rwops or SMPEG_new_data, the integer wrap leads to either a reachable assertion or an out‑of‑bounds copy, which results in the application crashing. Because the exploit merely causes a crash, the primary impact is denial of service against that application.

The affected product is smpeg from icculus. Versions up to and including 2.0.0 are vulnerable. No newer releases are specified in the CVE description.

The CVSS score of 6.8 classifies the weakness as a medium‑severity problem. EPSS is not available, and the vulnerability is not listed in the CISA KEV catalog, indicating that no widespread exploitation has been reported so far. The likely attack vector is local or from an untrusted MPEG file that a user can supply to an application that uses smpeg. If an attacker can supply such a file, they can trigger a crash, but the CVE does not describe any further escalation or remote code execution path. Overall, the risk is moderate, but the denial of service effect could be significant if smpeg is part of a critical service.