Hello,
for professional reasons, I am unfortunately(!) dependent on the Cisco Secureclient 5. However, this has refused to work for some time now. To be precise, since an update of the libxml2 package.
My problem is very similar to the one already described in the ArchLinux forum. I’m sorry, I’m not sure if it is desired or allowed to post a URL to other forums here.
https://bbs.archlinux.org/viewtopic.php?id=290520
Unfortunately the workaround does not work for me. 
I am using Cisco Secureclient version 5.0.0.3072.
I updated from libxml2 from “2.11.5-1” to “2.12.3-1”.
I have installed the Cisco Secureclient under (/opt/cisco/secureclient). The client can also be called up. However, nothing happens when I try to connect to the VPN.
I copied the two files to /opt/cisco/secureclient/libxml as described in the ArchLinux forum workaround.
[michael@caladan libxml]$ ls -l
insgesamt 2864
-rwxr-xr-x 1 root root 1474064 22. Dez 12:47 libxml2.so.2
-rwxr-xr-x 1 root root 1457584 22. Dez 12:20 libxml2.so.2.11.5
[michael@caladan libxml]$ file libxml2.so.2
libxml2.so.2: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=abc05a092ba7b2e0f02b7ebea1c415f62d24186f, stripped
[michael@caladan libxml]$ file libxml2.so.2.11.5
libxml2.so.2.11.5: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=478f94fb417765d4c59b415ef79fd4302a71b8a5, stripped
In the file /usr/share/applications/com.cisco.secureclient.gui.desktop I added the following entry:
Exec=env LD_LIBRARY_PATH=“/opt/cisco/secureclient/libxml:$LD_LIBRARY_PATH” /opt/cisco/secureclient/bin/vpnui -execv_instanceq
I have installed the following package:
[michael@caladan libxml]$ sudo pacman -Qi libxml2
Name : libxml2
Version : 2.12.3-1
Architecture : x86_64
When I call up the Secureclient via the terminal, it displays the following message.
[michael@caladan bin]$ ./vpnui
(com.cisco.secureclient.gui:22800): Gtk-CRITICAL **: 15:13:15.369: gtk_widget_get_scale_factor: assertion ‘GTK_IS_WIDGET (widget)’ failed
However, I have installed the package. 
[michael@caladan bin]$ sudo pacman -Qi webkit2gtk
Name : webkit2gtk
Version : 2.42.4-1
Architecture : x86_64
A downgrade of the package libxml2 version “2.11.5-1” unfortunately only worked until a few days before Christmas (~ December 20th). Until then, the secureclient had worked flawlessly.
It would be really great if I could find some support for this problem. I’m pretty clueless at the moment.
Thank you.