---
id: CVE-2026-74470
title: 'scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write'
summary: |-
  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…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ebacb44cb2042b90951140eda806bedad23ef554 <
    7b615fc139e35c81077046df44725c532f7e2404
  - >-
    Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa <
    5d3e1d006bbb543259f9e31824caadbfff6a5465
  - >-
    Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa <
    49e5b25a0b74dbac595f122e5608fdce2918cc4e
  - >-
    Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa <
    495058429ca55ab7fcc21977b63b92907ad68066
  - >-
    Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa <
    2047ed09bf13453b7d6f9431b112ec07984dd69b
  - >-
    Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa <
    d6e6da6bc3b53231fac77ffab428da8173ee729c
  - >-
    Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa <
    93dde0bf2f39a0f9f57fd610aa3201ce5b753433
  - Linux c4d2d7c935a4ad20e8e726ca10499cefe4537103
  - Linux >= 5.15.8 < 5.15.217
  - Linux >= 5.10.85 < 5.11
  - Linux 5.16
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T18:57:17.506626Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:05:47.666Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74470'
references:
  - url: 'https://git.kernel.org/stable/c/7b615fc139e35c81077046df44725c532f7e2404'
  - url: 'https://git.kernel.org/stable/c/5d3e1d006bbb543259f9e31824caadbfff6a5465'
  - url: 'https://git.kernel.org/stable/c/49e5b25a0b74dbac595f122e5608fdce2918cc4e'
  - url: 'https://git.kernel.org/stable/c/495058429ca55ab7fcc21977b63b92907ad68066'
  - url: 'https://git.kernel.org/stable/c/2047ed09bf13453b7d6f9431b112ec07984dd69b'
  - url: 'https://git.kernel.org/stable/c/d6e6da6bc3b53231fac77ffab428da8173ee729c'
  - url: 'https://git.kernel.org/stable/c/93dde0bf2f39a0f9f57fd610aa3201ce5b753433'
tags:
  - cve.org
epss: 0.00129
epssPercentile: 0.02277
ingestedAt: '2026-10-16T19:46:24.359Z'
---

## Overview

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.

## Affected

- `Linux >= ebacb44cb2042b90951140eda806bedad23ef554 < 7b615fc139e35c81077046df44725c532f7e2404`
- `Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa < 5d3e1d006bbb543259f9e31824caadbfff6a5465`
- `Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa < 49e5b25a0b74dbac595f122e5608fdce2918cc4e`
- `Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa < 495058429ca55ab7fcc21977b63b92907ad68066`
- `Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa < 2047ed09bf13453b7d6f9431b112ec07984dd69b`
- `Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa < d6e6da6bc3b53231fac77ffab428da8173ee729c`
- `Linux >= 7db0e0c8190a086ef92ce5bb960836cde49540aa < 93dde0bf2f39a0f9f57fd610aa3201ce5b753433`
- `Linux c4d2d7c935a4ad20e8e726ca10499cefe4537103`
- `Linux >= 5.15.8 < 5.15.217`
- `Linux >= 5.10.85 < 5.11`
- `Linux 5.16`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.