An issue was discovered in libexif before 0.6.22. An unrestricted size in handling Canon EXIF MakerNote data could lead to consumption of large amounts of compute time for decoding EXIF data.
https://usn.ubuntu.com/4396-1/
https://security.gentoo.org/glsa/202007-05
https://lists.debian.org/debian-lts-announce/2020/05/msg00025.html
https://github.com/libexif/libexif/commit/e6a38a1a23ba94d139b1fa2cd4519fdcfe3c9bab
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00017.html