---
id: CVE-2026-64232
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  block: recompute nr_integrity_segments in blk_insert_cloned_request

  blk_insert_cloned_request() already recomputes nr_phys_segments
  against the bottom queue, because "…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  block: recompute nr_integrity_segments in blk_insert_cloned_request

  blk_insert_cloned_request() already recomputes nr_phys_segments
  against the bottom queue, because "…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
published: '2026-07-24'
updated: '2026-07-27'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64232'
references:
  - url: 'https://git.kernel.org/stable/c/0943f81e1b3176f27dbaf6db268fc69d8a94f0ba'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2c6e6a18a37b905cb584eb0dda3ae482162a81ca'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/42929c98d044f126508baf54a65b0f87f932fa75'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/53a01bcc0242590eda4c452a5bd996f62457113b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00457
epssPercentile: 0.38981
ingestedAt: '2026-07-27T06:16:49.318Z'
---

## Overview

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

block: recompute nr_integrity_segments in blk_insert_cloned_request

blk_insert_cloned_request() already recomputes nr_phys_segments
against the bottom queue, because "the queue settings related to
segment counting may differ from the original queue." The exact same
reasoning applies to integrity segments: a stacked driver's underlying
queue can have tighter virt_boundary_mask, seg_boundary_mask, or
max_segment_size than the top queue, in which case
blk_rq_count_integrity_sg() against the bottom queue produces a
different count than the cached rq->nr_integrity_segments inherited
from the source request by blk_rq_prep_clone().

When the cached count is lower than the bottom queue's actual count,
blk_rq_map_integrity_sg() trips

	BUG_ON(segments > rq->nr_integrity_segments);

on dispatch. The same families of stacked setups that motivated the
existing nr_phys_segments recompute -- dm-multipath fanning out to
nvme-rdma in particular -- can produce this.

Mirror the nr_phys_segments handling: when the request carries
integrity, recompute nr_integrity_segments against the bottom queue
and reject the request if it exceeds the bottom queue's
max_integrity_segments. blk_rq_count_integrity_sg() and
queue_max_integrity_segments() are both already available via
<linux/blk-integrity.h>, which blk-mq.c includes.

This closes a latent gap in the stacking contract and brings the
integrity-segment accounting in line with the existing
phys-segment accounting.

## Remediation

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