Filters non-printable characters from process names. See #504144 in Debian BTS.
Index: htop/RichString.c
===================================================================
--- htop.orig/RichString.c	2008-12-06 11:13:19.679940957 +0200
+++ htop/RichString.c	2008-12-06 11:14:57.454712750 +0200
@@ -89,7 +89,7 @@
 inline void RichString_appendn(RichString* this, int attrs, char* data_c, int len) {
    int last = MIN(RICHSTRING_MAXLEN - 1, len + this->len);
    for (int i = this->len, j = 0; i < last; i++, j++)
-      this->chstr[i] = data_c[j] | attrs;
+      this->chstr[i] = (isprint(data_c[j]) ? data_c[j] : '?') | attrs;
    this->chstr[last] = 0;
    this->len = last;
 }