CVE-2026-90216

In the Linux kernel, the following vulnerability has been resolved:

ubi: Fix rollback for explicit UBI device numbers

ubi_init_attach() rolls back module initialization failures by scanning
ubi_devices[0..i-1], where i is the mtd= parameter index. That assumes
the parameter index matches the UBI device number.

That assumption is not true when mtd= specifies an explicit ubi_num. A
successfully attached device can be stored at a higher ubi_devices[]
slot, and a later failure can miss it during rollback.

Scan the full ubi_devices[] array and detach by the actual array index,
matching the way UBI devices are stored.