If you try to use a exFAT formatted flash drive or (more likely) microSD card from your Android phone on Fedora 26, you might get an error saying something about exFAT. This article https://coderwall.com/p/nvwgea/mounting-exfat-formatted-pendrives-in-fedora-linux from last year is still valid.
Firstly, enable RPM Fusion if you haven't already at https://rpmfusion.org/Configuration
Then, you can go to the terminal and do a sudo dnf install fuse-exfat.
You will see something like what's below for Fedora 26.
---
[panda@panda ~]$ dnf search fuse-exfat
Last metadata expiration check: 1 day, 19:39:11 ago on Fri 14 Jul 2017 10:12:25 PM EDT.
======================================================================================== Name Exactly Matched: fuse-exfat =========================================================================================
fuse-exfat.x86_64 : Free exFAT file system implementation
[panda@panda ~]$ dnf install fuse-exfat
Error: This command has to be run under the root user.
[panda@panda ~]$ sudo dnf install fuse-exfat
[sudo] password for panda:
Fedora 26 - x86_64 - Updates 4.6 MB/s | 4.6 MB 00:01
Last metadata expiration check: 0:00:01 ago on Sun 16 Jul 2017 05:51:54 PM EDT.
Dependencies resolved.
===================================================================================================================================================================================================================
Package Arch Version Repository Size
===================================================================================================================================================================================================================
Installing:
fuse-exfat x86_64 1.2.7-1.fc26 rpmfusion-free 42 k
Transaction Summary
===================================================================================================================================================================================================================
Install 1 Package
Total download size: 42 k
Installed size: 74 k
Is this ok [y/N]: y
Downloading Packages:
fuse-exfat-1.2.7-1.fc26.x86_64.rpm 556 kB/s | 42 kB 00:00
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 67 kB/s | 42 kB 00:00
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Installing : fuse-exfat-1.2.7-1.fc26.x86_64 1/1
Running scriptlet: fuse-exfat-1.2.7-1.fc26.x86_64 1/1
Verifying : fuse-exfat-1.2.7-1.fc26.x86_64 1/1
Installed:
fuse-exfat.x86_64 1.2.7-1.fc26
Complete!
[panda@panda ~]$