Italy's long coast is vulnerable to the Royal Navy ships in the Mediterranean and the west is open to a French invasion, unless the Germans manage to tie enough allied troops on the Somme. If the CP are defeated, I expect Italy to fall first. Before the Ottomans and probably even before Bulgaria, too. The Savoias would be surely overthrown and, being so unpopular the alliance with Austria-Hungary*, it's not entirely impossible to see the new republican (or even socialist) Italian government changing sides and still opening the third front in the Veneto.
In that scenario, though, Italy is going to lose the colonies and perhaps something more anyway, and if there are gains they are going to be minimal. The frontiers drawn at *Versailles will be based purely on idiomatic differences, so Republican Italy will still gain Trento and Trieste, but not South Tirol (which wil remain Austrian) nor Istria (which will go to the Kingdom of the Serbs, Croats and Slovenes).
France and Britain would divide Eritrea and Somalia between them, but I don't know what could take each one. There would be a redrawn of the Franco-Italian border giving some strategic points in the Alps to France. I have also the pet idea (don't know if this is feasible) that Sardinia could end up as a League of Nations Mandate under Franco-British occupation and ultimately would end as an independent republic. The Italian fleet, if not already destroyed in the war, would be largely dismantled.
Finally, I expect the new Italian state to be very unstable and lead to the raising of something like Mussolini sooner or later, but without the popularity this enjoyed in the 20s and early 30s. The Empire of Ethiopia and the Kingdom of Albania would still be independent nations when WW2 breaks out, if it still does.
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*It was Umberto I who signed this alliance which, combined with his imperialist ambitions in East Africa that lead to the disastrous battle of Adwa, mined his popularity and probably bought the bullet that killed him in 1900. Umberto not being killed and still reigining in 1914 could be a decent POD for this TL.