The gdImageCropThreshold function in gd_crop.c in the GD Graphics Library (aka libgd) before 2.2.3, as used in PHP before 7.0.9, allows remote attackers to cause a denial of service (application crash) via an invalid color index.
libgd - Denial of Service via Negative Color Value in gdImageFillToBorder
Stack consumption vulnerability in the gdImageFillToBorder function in gd.c in the GD Graphics Library (aka libgd) before 2.2.2, as used in PHP before 5.6.28 and 7.x before 7.0.13, allows remote attackers to cause a denial of service (segmentation violation) via a crafted imagefilltoborder call that triggers use of a negative color value.