The Liberating (WMH) weapon property allows the wielder to dispel an ongoing spell effect inhibiting movement through a combat maneuver.
The Weapon Finesse vs CMB FAQ states:
Weapon Finesse: If I have this feat, can I apply my Dex bonus to my combat maneuver checks instead of my Strength bonus?
It depends on what combat maneuver you're attempting. Disarm, sunder, and trip are normally the only kinds of combat maneuvers in which you’re actually using a weapon to perform the maneuver, and therefore the weapon’s bonuses apply to the roll. Therefore, if you're attempting a disarm, sunder, or trip maneuver, you can apply your Dex bonus instead of your Str mod on the combat maneuver check (assuming you're using a finessable weapon, of course). For other combat maneuvers, you use the normal rule for determining CMB (Str instead of Dex).
Notice the "normally" highlighted in the text. Would the combat maneuver produced by a Liberating weapon count as an exception to the norm? Being this a weapon property, would it count as a "combat maneuver in which you’re actually using a weapon to perform the maneuver" for the purposes of applying the weapon's bonuses to the roll?
Bump + example:
8th level Small Rogue (8 Str, 18 Dex) with Weapon Finesse, wielding a +1 Liberating Dagger, trying to snap himself out of Hold Person. What would the CMB be for the purposes of the Liberating combat maneuver?
a) The combat maneuver is not performed via the weapon: CMB = +6(BAB) -1(Str) -1(Small) = +4
b) The weapon is instrumental to the combat maneuver, which is performed through the weapon: CMB = +6(BAB) +4(Dex) -1(Small) +1(Enhancement) = +10