_TIFFCheckMalloc and _TIFFCheckRealloc in tif_aux.c in LibTIFF through 4.0.10 mishandle Integer Overflow checks because they rely on compiler behavior that is undefined by the applicable C standards. This can, for example, lead to an application crash.
https://www.debian.org/security/2020/dsa-4670
https://www.debian.org/security/2020/dsa-4608
https://seclists.org/bugtraq/2020/Jan/32
https://seclists.org/bugtraq/2019/Nov/5
https://lists.debian.org/debian-lts-announce/2019/08/msg00031.html
https://gitlab.com/libtiff/libtiff/merge_requests/90
http://packetstormsecurity.com/files/155095/Slackware-Security-Advisory-libtiff-Updates.html
http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00023.html
http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00102.html