diff --git a/src/imageformats/rgb.cpp b/src/imageformats/rgb.cpp
index 9f1d0dc..41b9ac9 100644
--- a/src/imageformats/rgb.cpp
+++ b/src/imageformats/rgb.cpp
@@ -338,6 +338,9 @@ bool SGIImagePrivate::readImage(QImage &img)
                 return false;
             }
         }
+        for (; l < _numrows; l++) {
+            _lengthtab[l] = 0;
+        }
     }
 
     if (_stream.status() != QDataStream::Ok) {