The flaw is a heap out‑of-bounds read in the gbr_open() function of gbsplay 0.0.103. The function does not verify the length of the GBR ROM title field before scanning it, allowing a crafted GBR file sized between 0x21 and 0x162 bytes to read memory beyond the buffer. The read can cause a crash or leak arbitrary data from the process heap. The weakness is classified as CWE‑125.

This vulnerability affects the gbsplay utility from the mmitch project, specifically the 0.0.103 release. Any environment running this exact version and processing GBR files is susceptible.

The CVSS score of 4.8 indicates moderate severity. The EPSS score is not available, and the vulnerability is not listed in the CISA KEV catalog, suggesting limited public exploitation data. The likely attack vector is local file‑based: a user can supply a malicious GBR file to invoke gbr_open(), causing the application to read beyond its heap buffer. No network or remote exploitation avenues are described, so the risk is confined to users who run gbsplay with untrusted input.