A flaw was found in OpenJPEG’s encoder in the opj_dwt_calc_explicit_stepsizes() function. This flaw allows an attacker who can supply crafted input to decomposition levels to cause a buffer overflow. The highest threat from this vulnerability is to system availability.
https://bugzilla.redhat.com/show_bug.cgi?id=1905723
https://lists.debian.org/debian-lts-announce/2021/02/msg00011.html