CVE-2026-89718

/// Technical description

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

zram: fix out-of-bounds access in writeback_store()

Patch series "zram: fix stale scan bounds after reinitialization".

Both writeback_store() and read_block_state() derive their table scan

bounds from zram->disksize before acquiring dev_lock. If the device is

reset and reinitialized with a smaller disksize between that read and lock

acquisition, the bound can describe the old table while the scan operates

on the new one. This can lead to out-of-bounds slot accesses.

Move both bound calculations under dev_lock so each bound remains

consistent with the table throughout its scan. Keep the fixes separate

because the affected interfaces originate from different commits and can

be backported independently.

This patch (of 2):

writeback_store() calculates the table scan bounds before taking dev_lock.

A reset followed by reconfiguration with a smaller disksize can therefore

replace zram->table while writeback_store()

/// 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