Yes, almost all vanilla extracts (even artificial ones) are vegan.
I’ve never come across one that wasn’t.
Some contain castoreum (from a beaver’s anal glands), but it’s exceedingly rare nowadays because it’s difficult and expensive to gather.
Vanilla extract (the real stuff) is made by breaking up vanilla pods and filtering them through a mixture of ethanol and water.
No concerns there.
The artificial vanilla extract, which you can easily identify by the cheap price, is synthesized from guaiacol, a by-product of the wood pulp industry.
Either way, it doesn’t come in contact with or contain any animal products.
If you really want to be sure that a vanilla extract doesn’t contain castoreum, contact the manufacturer.