diff --git a/app/core/core-types.h b/app/core/core-types.h
index 990be94727..75a8526f0b 100644
--- a/app/core/core-types.h
+++ b/app/core/core-types.h
@@ -30,7 +30,7 @@
 
 /*  former base/ defines  */
 
-#define MAX_CHANNELS  4
+#define MAX_CHANNELS  5
 
 #define RED           0
 #define GREEN         1
diff --git a/app/core/gimpbrush-transform.cc b/app/core/gimpbrush-transform.cc
index 45673cd4f2..e36475b351 100644
--- a/app/core/gimpbrush-transform.cc
+++ b/app/core/gimpbrush-transform.cc
@@ -841,6 +841,9 @@ gimp_brush_transform_blur (GimpTempBuf *buf,
   if (rw <= 0 || rh <= 0)
     return;
 
+  /* Making sure we have enough elements for acc array. */
+  g_return_if_fail (components <= MAX_CHANNELS);
+
   sums = g_new (Sums, width * height * components);
 
   gegl_parallel_distribute_range (
@@ -866,7 +869,7 @@ gimp_brush_transform_blur (GimpTempBuf *buf,
             gint weighted_sum;
             gint leading_sum;
             gint leading_weighted_sum;
-          } acc[components];
+          } acc[MAX_CHANNELS];
 
           memset (acc, 0, sizeof (acc));
 
@@ -946,7 +949,7 @@ gimp_brush_transform_blur (GimpTempBuf *buf,
             gfloat weighted_sum;
             gint   leading_sum;
             gint   trailing_sum;
-          } acc[components];
+          } acc[MAX_CHANNELS];
 
           memset (acc, 0, sizeof (acc));
 
diff --git a/app/core/gimppickable-auto-shrink.c b/app/core/gimppickable-auto-shrink.c
index 7ddbee227c..c6b6186b51 100644
--- a/app/core/gimppickable-auto-shrink.c
+++ b/app/core/gimppickable-auto-shrink.c
@@ -72,7 +72,7 @@ gimp_pickable_auto_shrink (GimpPickable *pickable,
   GeglBuffer      *buffer;
   GeglRectangle    rect;
   ColorsEqualFunc  colors_equal_func;
-  guchar           bgcolor[MAX_CHANNELS] = { 0, 0, 0, 0 };
+  guchar           bgcolor[MAX_CHANNELS] = { 0 };
   guchar          *buf = NULL;
   gint             x1, y1, x2, y2;
   gint             width, height;
diff --git a/app/core/gimppickable-contiguous-region.cc b/app/core/gimppickable-contiguous-region.cc
index a099c7fcf6..433c3f5324 100644
--- a/app/core/gimppickable-contiguous-region.cc
+++ b/app/core/gimppickable-contiguous-region.cc
@@ -148,6 +148,9 @@ gimp_pickable_contiguous_region_by_seed (GimpPickable        *pickable,
 
   format = choose_format (src_buffer, select_criterion,
                           &n_components, &has_alpha);
+
+  g_return_val_if_fail (n_components <= MAX_CHANNELS, NULL);
+
   gegl_buffer_sample (src_buffer, x, y, NULL, start_col, format,
                       GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
 
@@ -228,6 +231,8 @@ gimp_pickable_contiguous_region_by_color (GimpPickable        *pickable,
   format = choose_format (src_buffer, select_criterion,
                           &n_components, &has_alpha);
 
+  g_return_val_if_fail (n_components <= MAX_CHANNELS, NULL);
+
   gegl_color_get_pixel (color, format, start_col);
 
   if (has_alpha)