Visitors traveling to the United States are required to be in possession of passports that are valid for six months beyond the period of their intended stay in the United States. Citizens of certain countries are exempt the six-month rule and need only have a passport valid for their intended period of stay.
When travelers come to the United States with a passport that will expire before the USCIS approved status expiration date, CBP may issue a Form I-94 with the expiration date equal the passport expiration date. For example, a traveler comes to U.S with an H-1B visa. She intends to stay for 3 years pursuant to the I-797 Approval Notice. However, her passport will expire in one year. In this case, when she enters, CBP may give her an I-94 with an expiration date not matching the I-797 but her passport expiration date.
Overstay of the Form I-94 expiration date starts the period of unlawful presence. The problem has to be fixed before the I-94 expires.
How to Fix it
CBP can issue a corrected I-94 card when the original I-94 contains errors. However, CBP offices may refuse to issue a corrected I-94 in above stated situation because the original I-94 expiration date was proper.
The traveler can file an application to extend status with USCIS. For H-1b visa holder, a new I-129, not I-539, should be used. Other visa holders may just file an I-539.
Finally, the traveler may leave the U.S. after obtaining a new passport. She can then re-enter and obtain a new I-94 with the expiration date matching the I-797.