Index: channels/chan_iax2.c
===================================================================
--- channels/chan_iax2.c	(revision 62039)
+++ channels/chan_iax2.c	(working copy)
@@ -6732,6 +6732,9 @@
 			ast_mutex_unlock(&iaxsl[fr->callno]);
 			return 1;
 		}
+		/* Ensure text frames are NULL-terminated */
+		if (f.frametype == AST_FRAME_TEXT && buf[res] != '\0')
+			buf[res++] = '\0';
 		f.datalen = res - sizeof(*fh);
 
 		/* Handle implicit ACKing unless this is an INVAL, and only if this is