CVE-2026-89953

/// Technical description

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

mtd: mtdoops: free page bitmap when the backing MTD is removed

mtdoops_notify_add() allocates oops_page_used when the configured MTD

device is registered. mtdoops_notify_remove() detaches from that device

but leaves the bitmap allocated. If the same MTD device is later

registered again, the add path allocates a new bitmap and overwrites the

old pointer, leaking one vmalloc allocation per remove/add cycle.

This is only visible when the backing MTD device can disappear and be

registered again while mtdoops remains loaded, so the usual static MTD

case does not expose it.

Free the bitmap after unregistering the dumper and flushing the pending

workers, then clear the pointer and page count before a later attach can

allocate fresh state. Clearing the pointer also keeps the module exit

path from freeing the same bitmap a second time after a remove event.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References