The X2Go project believes that X2Go Client for Windows 4.0.4.0-2015.06.24 and prior are affected by CVE-2015-1793 when connecting to a session broker via HTTPS. Therefore, users that connect to session brokers via HTTPS are encouraged to upgrade to 4.0.5.0 ASAP.
Note that there will be no more updates, including security updates, for 4.0.4.0. You must upgrade to 4.0.5.0 to continue receive future security updates.
The gist of bug bug #696 is that an X2Go Session started from X2Go Client for Windows 4.0.4.0 (and many/all earlier versions) could not be resumed on Linux or Mac clients. It also could not be resumed from X2Go Client for Windows under certain conditions (see the list of conditions below.)
When a session cannot be resumed, you would see the error message:
Failed to restore all the required visuals. Cant't resume the NX session on this display.
However, sessions affected by this issue can be resumed by the client from where it was started, or from other clients running X2Go Client for Windows 4.0.4.0 (or earlier) under the certain conditions, even after you failed to resume it on a different client.
The fix this bug is to make X2Go Client behave like Linux or Mac clients. Therefore, a session started on X2Go Client for Windows 4.0.4.0 (or earlier) (under the conditions specified below) cannot be resumed on X2Go Client for Windows 4.0.5.0. However, a session started on X2Go Client for Windows 4.0.5.0 can be resumed on any client.
The X2Go project therefore recommends that update all your Windows clients to 4.0.5.0 at the same time.
To determine if a session cannot be resumed, open up a terminal in the session and run:
xdpyinfo | grep -i StaticColor
If 1 line is outputted, then it cannot be resumed from those other clients. If no lines are outputted, then it can be.
If all of the conditions are met, then a session started cannot be resumed on other clients:
Note that there are multiple reasons why OpenGL support may not be enabled in the Windows OS:
There is only 1 build.
Both installers now include the regular build & the debug build of X2Go Client.
The regular installer, x2goclient-4.0.5.0-2015.07.31-setup.exe , is available under this folder:
X2Go Client is currently only released as a 32-bit x86 build. Both 32-bit x86 and 64-bit x86 versions of Windows are supported via this build.
These versions of Windows without the latest (specified) service pack may be compatible, but are rarely (if ever) tested. They are not officially supported.
Corresponding server versions of Windows are also supported, but receive minimal testing:
Any incompatibility or bug with a specific version of Windows should be reported via our bug-tracker.
See this page:
bug 696 Can't resume session started by Windows X2Go client with Linux X2Go client
bug 883 Window Decorations gone when resuming on smaller screen
bug 611 The server cannot be added to the known_hosts file (and thus you cannot connect to the server) when both of these conditions are met: 1. Your Windows username has non-English characters. 2 Those characters are in a different language than the Windows “system locale”.