Citing concerns that ongoing armed conflict within Yemen poses a continued and serious threat to the personal safety of nationals returning there, the U.S. Department of Homeland Security (DHS) redesignated the country for Temporary Protected Status (TPS) on January 4, 2017. (For a full background discussion, see the official Federal Register notice.)
DHS extended Yemen's existing TPS designation for 18 months, which will start March 4, 2017 and end September 3, 2018. This allows eligible nationals of Yemen (or people with no nationality who last habitually resided in Yemen) to register or re-register for this limited right to live and work in the United States.
In order to extend your TPS if you have it already, you will need to submit an application to U.S. Citizenship and Immigration Services (USCIS) between January 4 and March 6, 2017. You can apply for a new Employment Authorization Document (EAD) at the same time; your EAD card will come with an expiration date of September 3, 2018. In case your new EAD doesn't arrive before the old one expires, however, USCIS is automatically extending current TPS Yemen EADs with an expiration date of March 3, 2017 to September 3, 2017.
(If your employer has any questions about you working with a supposedly expired EAD, you might direct it to Nolo's article, Why Employees With TPS Might Legally Work Past Expiration Date on Work Permit.)
Go to the USCIS Temporary Protected Status Designated Country: Yemen page for details and links to application forms and instructions.