I'm going to start off with saying I am a certificated aircraft mechanic, and I've been exercising my privileges as such for several years on both passenger and cargo aircraft for several airframes.

This situation is actually a VERY big deal and it is going to be VERY expensive and time consuming to fix.

When a part is sold or repaired by a manufacturer, it comes with an airworthiness certificate. In the US, this is FAA form 8130-3. It not only certifies that the part conforms to specifications; but it shows who certified it, who tested it, what specs it meets, and the history of the part. Both the airline purchasing the part and the mechanic installing the part need this document to legally repair the aircraft.

There could be a variety of problems with receiving fake parts that slip by SUP inspections (Suspected Unapproved Parts), and these are both legal and safety problems. A fake serial number means you don't know the true history of the part. It could have been pulled from an abandoned aircraft from a third world country, and even though it passed a bench test, it could be a ticking time bomb. It could be a part in exceedence of service hours, but the paperwork that came with it says it's freshly overhauled.

It could just plain not meet specifications. Premature failure is a big deal. Especially when the list of things that can be broken on a plane (MEL / Missing Equipment List) and still be safe for flight depend on a rated level of reliability. As an example, an aircraft can operate with a certain number of brakes not working for a limited period of time (such as up to two inoperative, no more than one per pair, for no longer than 10 days or 10 flight cycles). This assumes that all of your other brakes aren't going to prematurely, simultaneously fail before that time limit is up.

This article specified that these are engine parts, which adds a whole other level of risk to flight safety. The CFM56 from this article can be rated for ETOPS 180, which stands for Extended Operations up to 180 minutes. Normally, twin-engine aircraft are required to remain with 60 minutes of a suitable airport in the event of an emergency. This often limits what routes certain aircraft can take. ETOPS allows certain aircraft to go farther than the 60-minute rule (in this case, up to 180 minutes), which is a huge deal in terms of flight time, efficiency, and simply whether or not they can fly internationally. To maintain ETOPS rating, the aircraft has to meet stricter specifications. These can range anywhere from parts with tighter tolerances, to things like larger oxygen and fire-extinguishing bottles. They also need to be able to start their APU in flight for a source of electricity in the event they lose an engine.

The airline is also limited on the number of in-flight shutdowns they can have. This number is intentionally very low. If the airline as a whole exceeds this number, their fleet-wide ETOPS rating will be revoked.

Parts have to be specifically rated for ETOPS to be installed on an aircraft flying ETOPS routes. Bad parts make this a huge risk. An in-flight shutdown is a very dangerous situation, and bad parts dramatically increase the risk of that becoming a dual engine failure while that plane spends 3 hrs diverting to the closest airport.

Going forward, there is no good way to check if the parts sold actually meet specs until they're disassembled and checked. Directives from the FAA will be issued. Inspections will be performed. Airplanes will be grounded and rectified. The manufacturer might be able to provide a list of parts that need to be recalled, but more than likely EVERY part they issued will be pulled. They may also have their repair station and manufacturing certificate from GE revoked. Even if they don't lose their certification, most of the airlines will avoid them now.

To address the points you made in your comment, lefixxx, false documents mean bad parts. These parts absolutely DO pose a safety risk. They very likely ARE out of spec, timed out, or simply not rated for what the papers say. Even if the part is tested and meets specs, the history of that part is lost. It will need to be overhauled and made "new" again in order to be airworthy.
All of the regulations and strict document control requirements we follow have all been written in blood. People HAVE died because of things like this in the past, and it's our mission to keep it from ever happening again.

Edit:
Here's an excellent article detailing Partnair Flight 394, and the aftermath wherein they discovered a plethora of counterfeit parts not only on the airplane, but also across the industry at the time: https://admiralcloudberg.medium.com/riven-by-deceit-the-crash-of-partnair-flight-394-f8a752f663f8