decompress_gunzip.c in BusyBox through 1.32.1 mishandles the error bit on the huft_build result pointer, with a resultant invalid free or segmentation fault, via malformed gzip data.
https://security.gentoo.org/glsa/202105-09
https://lists.debian.org/debian-lts-announce/2021/04/msg00001.html
https://git.busybox.net/busybox/commit/?id=f25d254dfd4243698c31a4f3153d4ac72aa9e9bd