"Enable runtime UEFI media validation" checkbox breaks Ubuntu 26.04 installer

Checklist

• I have been made aware that if my problem can be summarized as "I've created or tried to create a media using Rufus, and ...", and I am not including a log, this issue will be summarily closed.
• I looked at https://github.com/pbatard/rufus/wiki/FAQ to see if my question has already been answered.
• I performed a search in the issue tracker for similar issues using keywords relevant to my problem, such as the error message I got from the log.
• I clicked the 'Log' button (🗒️) or pressed Ctrl-L in Rufus, or used DebugView, and copy/pasted the log into the section that says <FULL LOG> below.
• The log I am copying is the FULL log, starting with the line Rufus version: x.y.z - I have NOT removed any part of it.

Additionally (if applicable):

• I ran a bad blocks check, by clicking Show advanced format options then Check device for bad blocks, and confirmed that my USB is not defective.
• I also tried one or more of the following:
  • Using a different USB drive.
  • Plugging the USB into a different port.
  • Running Rufus on a different computer.
• If using an image, I clicked on the (✓) button to compute the MD5, SHA1 and SHA256 checksums, which are therefore present in the log I copied. I confirmed, by performing an internet search, that these values match the ones from the official image.

Issue description

If you enable that checkbox while creating a Ubuntu install media, your EFI/boot will look like this:

bootx64.efi
bootx64_original.efi

because it inserts its own EFI file that first validates the media, and then executes the original EFI.

Then while installing Ubuntu, you'll get a very unhelpful "Something went wrong" screen as the installer tries to show you disk partitions, and then the install won't proceed any further.
If you dig hard enough through logs then you'll see it's caused by:

unexpected multiple matches for installer shim obtained using globbing pattern ".*/cdrom/EFI/boot/boot*.efi"
which was introduced in snapd by this commit (pull request) in June 2025.

This is not an issue if you install Ubuntu without that checkbox checked, as then there's only one bootx64.efi.
I verified that by manually deleting bootx64.efi and then manually renaming bootx64_original.efi into bootx64.efi, after which the install succeeded without any other changes.

Start with src/hash.c around line 2540 and reproduce Ubuntu 26.04 media creation with “Enable runtime UEFI media validation” enabled. Compare the resulting EFI files with the installer behavior and snapd's globbing case in overlord/install/install_test.go. Done means the validated media can proceed through the Ubuntu installer without the multiple-match failure.