We don't pass anything over cmd line, what exactly do you have on mind?

These parts of VpncUiPlugin::importConnectionSettings() in vpnplugins/vpnc/vpnc.cpp:

        else if (!decrPlugin->readStringKeyValue(cg,"enc_UserPassword").isEmpty() && !ciscoDecryptBinary.isEmpty()) {
            // Decrypt the password and insert into map
            decrArgs.clear();
            decrArgs << decrPlugin->readStringKeyValue(cg,"enc_UserPassword");
            decrPlugin->ciscoDecrypt->setProgram(ciscoDecryptBinary, decrArgs);
            decrPlugin->ciscoDecrypt->start();
            if (decrPlugin->ciscoDecrypt->waitForStarted() && decrPlugin->ciscoDecrypt->waitForFinished()) {
                secretData.insert(NM_VPNC_KEY_XAUTH_PASSWORD, decrPlugin->decryptedPasswd);
            }
        }
…
        else if (!decrPlugin->readStringKeyValue(cg,"enc_GroupPwd").isEmpty() && !ciscoDecryptBinary.isEmpty()) {
            //Decrypt the password and insert into map
            decrArgs.clear();
            decrArgs << decrPlugin->readStringKeyValue(cg,"enc_GroupPwd");
            decrPlugin->ciscoDecrypt->setProgram(ciscoDecryptBinary, decrArgs);
            decrPlugin->ciscoDecrypt->start();
            if (decrPlugin->ciscoDecrypt->waitForStarted() && decrPlugin->ciscoDecrypt->waitForFinished()) {
                secretData.insert(NM_VPNC_KEY_SECRET, decrPlugin->decryptedPasswd);
                data.insert(NM_VPNC_KEY_SECRET"-flags", QString::number(Knm::Setting::AgentOwned));
            }
        }

The password-equivalent is passed over the command line to the cisco-decrypt program.

Fix committed here: http://commits.kde.org/plasma-nm/16b0df71b48c637884278e0f6a746c6909327c4e

It will be available with the next version

(In reply to Lukáš Tinkl from comment #3)
> Fix committed here:
> http://commits.kde.org/plasma-nm/16b0df71b48c637884278e0f6a746c6909327c4e
> 
> It will be available with the next version

Thanks.  Have you tested this?  I couldn't find the required functionality in the cisco-decrypt versions I tested.

Nope I haven't tested it... I kinda assumed the cisco-decrypt binary already supports it

kde-plasma-nm-0.9.3.1-5.fc20 has been submitted as an update for Fedora 20.
https://admin.fedoraproject.org/updates/kde-plasma-nm-0.9.3.1-5.fc20

Package kde-plasma-nm-0.9.3.1-5.fc20:
* should fix your issue,
* was pushed to the Fedora 20 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing kde-plasma-nm-0.9.3.1-5.fc20'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2013-19756/kde-plasma-nm-0.9.3.1-5.fc20
then log in and leave karma (feedback).

kde-plasma-nm-0.9.3.1-6.fc20 has been submitted as an update for Fedora 20.
https://admin.fedoraproject.org/updates/kde-plasma-nm-0.9.3.1-6.fc20

Package kde-plasma-nm-0.9.3.1-6.fc20:
* should fix your issue,
* was pushed to the Fedora 20 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing kde-plasma-nm-0.9.3.1-6.fc20'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2013-20837/kde-plasma-nm-0.9.3.1-6.fc20
then log in and leave karma (feedback).

kde-plasma-nm-0.9.3.1-6.fc20 has been pushed to the Fedora 20 stable repository.  If problems still persist, please make note of it in this bug report.