CVE-2026-74470

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

scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write

resp_report_zones() sizes the reply buffer from the CDB allocation

length. The v3 fix rounds alloc_len up with ALIGN() before deriving the

descriptor count:

rep_max_zones = (ALIGN((u64)alloc_len, RZONES_DESC_HD) -

RZONES_DESC_HD) >> ilog2(RZONES_DESC_HD);

arr_len = (u64)RZONES_DESC_HD * (rep_max_zones + 1);

For alloc_len in 0xFFFFFFC1..0xFFFFFFFF, ALIGN() rounds up to

0x100000000, so arr_len is 4 GB. On 32-bit, kzalloc()'s size_t is 32-bit

and truncates 0x100000000 to 0; kzalloc(0) returns ZERO_SIZE_PTR, which

passes the !arr check, and desc = arr + 64 is then dereferenced in the

loop -> out-of-bounds write / panic.

Clamp rep_max_zones to devip->nr_zones. The loop already stops at

sdebug_capacity (after nr_zones zones), so a report can never hold more

than nr_zones descriptors; the clamp does not change the report, it only

bounds arr_len to (nr_zones + 1) * RZONES_DESC_HD, a real device

property that can never reach 0x100000000.