diff --git a/src/libslic3r/EdgeGrid.hpp b/src/libslic3r/EdgeGrid.hpp
index 744a23e186..6bbed1e9fa 100644
--- a/src/libslic3r/EdgeGrid.hpp
+++ b/src/libslic3r/EdgeGrid.hpp
@@ -224,6 +224,8 @@ public:
 						iy += 1;
 						assert(iy <= iyb);
 					}
+					if (ix < 0 || iy < 0 || ix >= (int64_t)m_cols || iy >= (int64_t)m_rows)
+						return; 
 					if (! visitor(iy, ix))
 						return;
 				} while (ix != ixb || iy != iyb);
@@ -245,6 +247,8 @@ public:
 						iy -= 1;
 						assert(iy >= iyb);
 					}
+					if (ix < 0 || iy < 0 || ix >= (int64_t)m_cols || iy >= (int64_t)m_rows)
+						return; 
 					if (! visitor(iy, ix))
 						return;
 				} while (ix != ixb || iy != iyb);
@@ -270,6 +274,8 @@ public:
 						iy += 1;
 						assert(iy <= iyb);
 					}
+					if (ix < 0 || iy < 0 || ix >= (int64_t)m_cols || iy >= (int64_t)m_rows)
+						return; 
 					if (! visitor(iy, ix))
 						return;
 				} while (ix != ixb || iy != iyb);
@@ -307,6 +313,8 @@ public:
 						iy -= 1;
 						assert(iy >= iyb);
 					}
+					if (ix < 0 || iy < 0 || ix >= (int64_t)m_cols || iy >= (int64_t)m_rows)
+						return; 
 					if (! visitor(iy, ix))
 						return;
 				} while (ix != ixb || iy != iyb);