An issue was discovered in Anti-Grain Geometry (AGG) 2.4 as used in SVG++ (aka svgpp) 1.2.3. A heap-based buffer overflow bug in svgpp_agg_render may lead to code execution. In the render_scanlines_aa_solid function, the blend_hline function is called repeatedly multiple times. blend_hline is equivalent to a loop containing write operations. Each call writes a piece of heap data, and multiple calls overwrite the data in the heap.