Is there a solution to keep plugins updated with wordpress by auto upgrade them without need to access to the admin panel every time?
Holy schmoly shadowpress - what a risky idea.
I imagine one could write a cron plugin to do it, BUT what a risk....Already the auto wordpress multi update feature makes it way too tempting to just hit the update button on a bunch of updates in one go.
Recommended 'safe' procedure for system upgrades is something along the lines of: 1) read the changelogs and test all upgrades on a local similar install first 2) make a backup before upgrading 3) apply updates individually, checking all is fine in between, possibly even making a new backup in between so you can rollback should an upgrade not agree with your site.
If one can cope with the fallout of an error one could skip a step... but going to full automated update sounds like a recipe for disaster.
Consider the likelihood/risk/impact balance:
eg: the likelihood of a tsunami causing a nuclear reactor to melt down may be low, but the impact if it does......
Given that plugins are written by a variety of 3rd party developers, theres is a strong likeihood of a clash of some kind. Also some plugins release major new features in an update and that sometimes requires human intervention.
That said - a look at the 'related' questions will show you that the question does come up now and then. eg: Real automated and unattended wordpress upgrade including plugins