diff --git a/gfx/thebes/src/gfxWindowsFonts.cpp b/gfx/thebes/src/gfxWindowsFonts.cpp
index c4a6a137536..fff7a6b3e0a 100644
--- a/gfx/thebes/src/gfxWindowsFonts.cpp
+++ b/gfx/thebes/src/gfxWindowsFonts.cpp
@@ -603,6 +603,7 @@ gfxWindowsTextRun::MeasureOrDrawFast(gfxContext *aContext,
 
         if (dxBuf != stackBuf)
             free(dxBuf);
+        free(cglyphs);
     }
 
     free(glyphs);