NULL pointer dereference in Linux kernel - CVE-2026-53165

Detailed vulnerability description

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a null pointer dereference race condition in iomap_finish_folio_read() when reporting buffered read errors during concurrent read completion and truncate operations. A local user can trigger a buffered read failure while racing read completion with truncate activity to cause a denial of service.

The issue occurs because the folio can be unlocked and detached before the error reporting path dereferences folio->mapping.

How to mitigate CVE-2026-53165

Sources

• https://git.kernel.org/stable/c/1ad453817a4077230d1ba88eb0868f05f824449a
• https://git.kernel.org/stable/c/2eea7f44b9c8b42fd7d3a1a87c06a7cd1b99c327