Integer underflow in the _gdContributionsAlloc function in gd_interpolation.c in the GD Graphics Library (aka libgd) before 2.2.4 allows remote attackers to have unspecified impact via vectors related to decrementing the u variable.
http://libgd.github.io/release-2.2.4.html
https://access.redhat.com/errata/RHSA-2019:2519
https://access.redhat.com/errata/RHSA-2019:3299
https://github.com/libgd/libgd/commit/60bfb401ad5a4a8ae995dcd36372fe15c71e1a35
http://www.debian.org/security/2017/dsa-3777