An issue was discovered in gif2apng 1.9. There is a heap-based buffer overflow within the main function. It allows an attacker to write data outside of the allocated buffer. The attacker has control over a part of the address that data is written to, control over the written data, and (to some extent) control over the amount of data that is written.
https://lists.debian.org/debian-lts-announce/2022/03/msg00008.html