As per the Department of Homeland Security, US-CERT/NIST Vulnerability Summary for CVE-2015-2890,
This vulnerability can only be exploited "locally", that is, someone would need physical access to your computer. That makes portable devices most vulnerable but PCs in areas with public access, or those stolen by someone breaking into your home are affected too. For a list of affected Dells, see this CERT Vulnerability Note. Even if your Dell is not listed, I recommend you visit the Dell website for your Dell to see if a new BIOS update is out that addresses this problem.
The BIOS implementation on Dell Latitude, OptiPlex, Precision Mobile Workstation, and Precision Workstation Client Solutions (CS) devices with model-dependent firmware before A21 does not enforce a BIOS_CNTL locking protection mechanism upon being woken from sleep, which allows local users to conduct EFI flash attacks by leveraging console access, a similar issue to CVE-2015-3692.
This vulnerability can only be exploited "locally", that is, someone would need physical access to your computer. That makes portable devices most vulnerable but PCs in areas with public access, or those stolen by someone breaking into your home are affected too. For a list of affected Dells, see this CERT Vulnerability Note. Even if your Dell is not listed, I recommend you visit the Dell website for your Dell to see if a new BIOS update is out that addresses this problem.