The article linked there is a pretty good analysis of the obstacles to challenging it in federal court just by virtue of the action occurring, but it doesn't foreclose all possibilities. (And it's not obviously illegal to me, but that's irrelevant to the standing question.)
Imagine this scenario: A loan servicer neglects to adjust the amount a student loan borrower owes based on this action (or views it as illegal and intentionally doesn't adjust it), and bills the old amount.
If the borrower pays the higher amount, they may have standing to reclaim the overpayment under the argument that it was validly canceled. If they are not in the same state as the servicer, diversity jurisdiction might allow this to occur in federal court, and this overpayment is probably sufficiently concrete, particularized, and personal to generate Article III standing.
If the borrower pays the Biden-adjusted lower amount, then debt collection efforts may start and there may be a credit report impact, when with correct servicer implementation of the cancelation no debt would be sent to collections. There are all sorts of opportunities for standing to be created here, such as if a federal or state debt collection statute is violated by the servicer or if the borrower has another financial consequence (like a refused or higher-rate mortgage) from the inaccurately reduced credit score.
If any of this manages to land in state court, standing requirements can constitutionally be weaker anyway depending on the requirements of the state constitution.
So, we'll see, but it can probably be tested in the courts somehow, unless the Administrative Procedure Act rules somehow preempt any other lawsuit at all from using "Biden's action was illegal" as an argument in the service of some other cause of action.
Imagine this scenario: A loan servicer neglects to adjust the amount a student loan borrower owes based on this action (or views it as illegal and intentionally doesn't adjust it), and bills the old amount.
If the borrower pays the higher amount, they may have standing to reclaim the overpayment under the argument that it was validly canceled. If they are not in the same state as the servicer, diversity jurisdiction might allow this to occur in federal court, and this overpayment is probably sufficiently concrete, particularized, and personal to generate Article III standing.
If the borrower pays the Biden-adjusted lower amount, then debt collection efforts may start and there may be a credit report impact, when with correct servicer implementation of the cancelation no debt would be sent to collections. There are all sorts of opportunities for standing to be created here, such as if a federal or state debt collection statute is violated by the servicer or if the borrower has another financial consequence (like a refused or higher-rate mortgage) from the inaccurately reduced credit score.
If any of this manages to land in state court, standing requirements can constitutionally be weaker anyway depending on the requirements of the state constitution.
So, we'll see, but it can probably be tested in the courts somehow, unless the Administrative Procedure Act rules somehow preempt any other lawsuit at all from using "Biden's action was illegal" as an argument in the service of some other cause of action.