Index: main/dsp.c
===================================================================
--- main/dsp.c	(revision 265315)
+++ main/dsp.c	(working copy)
@@ -1415,7 +1415,7 @@
 				}
 				memmove(&dsp->digit_state.digits[0], &dsp->digit_state.digits[1], dsp->digit_state.current_digits);
 				dsp->digit_state.current_digits--;
-				memmove(&dsp->digit_state.digitlen[0], &dsp->digit_state.digitlen[1], dsp->digit_state.current_len * sizeof(dsp->digit_state.digitlen[0]));
+				memmove(&dsp->digit_state.digitlen[0], &dsp->digit_state.digitlen[1], (MAX_DTMF_DIGITS - 1) * sizeof(dsp->digit_state.digitlen[0]));
 				dsp->digit_state.current_len--;
 				dsp->dtmf_began = 0;