telnetd does not strip out the TERMINFO, TERMINFO_DIRS, TERMPATH and
TERMCAP (when it starts with a '/') environment variables.

Apply by doing:
       cd /usr/src
       patch -p0 < 030_telnetd.patch

And then rebuild and install telnetd:
       cd libexec/telnetd
       make depend
       make
       make install

Index: libexec/telnetd/sys_term.c
===================================================================
RCS file: /cvs/src/libexec/telnetd/sys_term.c,v
retrieving revision 1.19
diff -u -r1.19 sys_term.c
--- libexec/telnetd/sys_term.c  2000/09/15 07:13:47     1.19
+++ libexec/telnetd/sys_term.c  2000/10/10 15:57:18
@@ -1850,6 +1850,10 @@
               if (strncmp(*cpp, "LD_", 3) &&
                   strncmp(*cpp, "_RLD_", 5) &&
                   strncmp(*cpp, "LIBPATH=", 8) &&
+                   strncmp(*cpp, "TERMINFO=", 9) &&
+                   strncmp(*cpp, "TERMINFO_DIRS=", 14) &&
+                   strncmp(*cpp, "TERMPATH=", 9) &&
+                   strncmp(*cpp, "TERMCAP=/", 9) &&
                   strncmp(*cpp, "ENV=", 4) &&
                   strncmp(*cpp, "IFS=", 4))
                       *cpp2++ = *cpp;