Linux Kernel Zram Component Use-After-Free Vulnerability in Writeback Bio Handling

A use-after-free vulnerability has been identified in the Zram component of the Linux kernel. This issue arises from a race condition between the bio completion handler and the writeback task, leading to a NULL pointer dereference. The vulnerability is present in the stable versions of the Linux kernel.

Impact

Exploitation of this vulnerability causes a crash due to a use-after-free condition, which can lead to memory corruption.

Reproduction

The vulnerability can be reproduced by introducing a race condition between the Zram bio completion handler and the writeback task. This can be done by submitting writeback requests that are processed before the completion handler has a chance to execute, causing the writeback control structure to be freed while it is still in use.

Remediation

Users can upgrade to the latest stable version of the Linux kernel, where this vulnerability has been fixed.