Factual error: The 2 C-class Mercedes Benz' they have in the CIA compound are the newer body styles that came out the year they were filming the movie. The Benghazi attack happened in 2012, the C-class had a different body style then.
Factual error: In the scene after the attack begins and military assets are spinning up to go help, when they briefly show the SOC guys loaded into a transport aircraft they all look operator-ish and have high cut fast helmets, but are carrying M16A4's with no optical devices mounted. I don't know of any SOCOM units that wear fast helmets but are issued A4's without an ACOG, ELCAN, aimpoint, etc. (00:15:00 - 01:25:00)
Factual error: When the analysts at the CIA Annex are discussing where the GRS operators are, the map they are looking at is not the actual Benghazi compound.
Factual error: When the militants are preparing to burn down the building, a contractor twice reports that they are spreading diesel around. Diesel does not burn under normal circumstances and will only combust under high temperature/pressure. (00:51:50 - 00:52:30)
Suggested correction: "Diesel does not burn under normal circumstances" FALSE. Just like it's Brethren Fuels, Jet - A and Kerosene, Diesel Fuel burns at the touch of a flame. Please don't conflate combustion with ignition.
Diesel will not ignite if you throw a flame into it. The flashpoint of diesel is approximately 140° Fahrenheit (60 Celsius). This means in most ambient temperatures it will not ignite. The fuel would not have ignited in the conditions show in the film.
Factual error: The movie is set in 2012. The S class Mercedes has a stereo camera as a sensor for advanced driver assistance systems, only introduced in 2013.
Factual error: Toward the end of the movie there is a shot over the Mediterranean Sea with the sun rising. The shoreline at Benghazi generally runs northeast-southwest, meaning the point of view would be somewhere between these two directions. If we assume that the point of view is generally straight out to sea, this would make the point of view northwest.
Factual error: Sean Smith is shown playing "Call of Duty: Advanced Warfare" on an Xbox. That game was released on November 4th, 2014, over two years after the date of the attack (September 11-12, 2012).
Suggested correction: It was Modern Warfare being shown on the TV. Advance warfare uses exo suits and can't be missed.