CVE-2026-90215: mtd: ubi: Release device reference on busy detach

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-17 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: mtd: ubi: Release device reference on busy detach ubi_detach_mtd_dev() obtains a device reference through ubi_get_device() before checking whether the UBI device is busy. The busy return path drops ubi->ref_count but leaves the device reference held, so the device object cannot be released after a later detach. Drop the device reference before returning -EBUSY.

Affected products

Linux kernel: 6.9 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/31dd710cd84d5dd63c49f640d3a9f36c9699ca95
https://git.kernel.org/stable/c/851c5e9a829d56cb0982965f07ef8966a6722884
https://git.kernel.org/stable/c/87812858c4c8df979cb70bcd0040b925a543df6f
https://git.kernel.org/stable/c/e065960366b55ab21e6c643c30dec2a41451900b

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