Is there any way an enemy can get past Bigby's interposing hand with a Strength score of less than 26?

Question

If my wizard casts Bigby's Hand (PHB, p. 218) (Interposing) between the PC and the enemy, is there any way an enemy can approach me if their Strength score is less than 26?

Interposing Hand. The hand interposes itself between you and a creature you choose until you give the hand a different command. The hand moves to stay between you and the target, providing you with half cover against the target. The target can't move through the hand's space if its Strength score is less than or equal to the hand's Strength score. If its Strength score is higher than the hand's Strength score, the target can move toward you through the hand's space, but that space is difficult terrain for the target.

Answer 1

That's what Bigby's Hand does when used in Interposing mode.

There is nothing preventing the incoming character from attempting to get around the hand - teleportation effects will do the job. Sure the hand will automatically move to interpose and still grant cover, but teleportation is not moving through the hand's space and not subject to the Strength issue.

Note that the hand itself is a large object, filling (albeit not completely) a 10×10 foot space. It prevents the target creature from getting any closer than that, but it doesn't stop it from attacking the Hand's caster with a ranged weapon or sufficient reach - it just gives half cover.

Probably the most important bit is that Interposing Hand only works against one target. It doesn't fill the space, so any creature other than the designated target can walk right through it. It's also a Concentration spell, which means hitting the caster hard enough or frequently enough can cause the spell to drop entirely.

Why would one use Grasping Hand instead?

Grasping Hand can grapple the target. A grappled target cannot move. Huge creatures often have reach, so the size of the hand may be insufficient to keep all creatures at bay - plus, those creatures are likely to be the ones with sufficient strength to power through Interposing Hand. Lock a creature down with Grasping Hand, and walk away.

And hey, you can crush them, too.

Why would one use Clenched Fist instead?

Clenched Fist and Grasping Hand both do damage, right? Sure... but Grasping Hand deals bludgeoning damage (a frequently resisted damage type) and Clenched Fist deals force damage (a rarely resisted damage type).

Why would one use Forceful Hand instead?

For the laughs, of course. Doesn't the idea of shoving people off of things with a ten foot hand make you chuckle?

TLDR

Bigby's Hand is a highly flexible spell. You have to pick the right mode for the right opponent.

Answer 2

Destroy the Hand: that gets it out of the way

From the spell description:

The hand is an object that has AC 20 and hit points equal to your hit point maximum.

Let's assume a 9th level wizard with a 14 constitution who can cast a level 5 spell. The hand would have 40 HP. Whomever wants to get at the spell caster can do 40 HP of damage to it, and then get after the spell caster. The trick to this is doing a form of damage that does damage to objects - and hitting AC 20. Some creatures, like Giants, will have an easier time of this than others.

Missile / ranged attacks; try to end the caster's concentration

Granted, the caster has the benefit of +2 to armor class (hand provides half cover in this mode) but the missile / ranged attacks can still reach the caster. A long bow fires at normal chances to hit at a range of 150', and gets disadvantage on attacks up to 600'. It's still a way to attack the caster, and any hit has a chance to disrupt the caster's concentration.

Those are two ways to get past the interposing hand, but it will take a few rounds, and the second depends upon the concentration roll being missed.

If able, summon a minion/ally

Depending on what class features, spells, and abilities a target creature has, getting past the hand may just need an ally since the Interposing hand only interposes between the caster and one creature.
Example? Beast Master Ranger. Here's a nice opportunity for that animal companion to shine: the Ranger can sacrifice her action to get the animal companion to attack the caster. (and if damage is done, there's a concentration check ...)