diff --git a/layout/base/nsCSSRenderingBorders.cpp b/layout/base/nsCSSRenderingBorders.cpp
index 789f411e670..3a6608e91d7 100644
--- a/layout/base/nsCSSRenderingBorders.cpp
+++ b/layout/base/nsCSSRenderingBorders.cpp
@@ -728,7 +728,7 @@ nsCSSBorderRenderer::DrawBorderSides(int aSides)
     return;
   }
 
-  uint8_t borderRenderStyle;
+  uint8_t borderRenderStyle = NS_STYLE_BORDER_STYLE_NONE;
   nscolor borderRenderColor;
   const nsBorderColors *compositeColors = nullptr;