# CVE-2026-64232: block: recompute nr_integrity_segments in blk_insert_cloned_request

> A missing integrity segment recomputation in the Linux kernel block layer can cause a kernel BUG_ON crash in stacked driver configurations.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-64232, DEBIAN-CVE-2026-64232, GHSA-g8pp-85q4-6cgq, ROOT-OS-UBUNTU-2204-CVE-2026-64232, UBUNTU-CVE-2026-64232

## What is CVE-2026-64232?

CVE-2026-64232 is a critical denial of service vulnerability in Linux kernel, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2026-64232?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64232?

Apply the vendor's patch.

## Is CVE-2026-64232 being exploited?

There is no known exploitation of CVE-2026-64232 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64232 and fix it if it is affected.

What it is: CVE-2026-64232 is a critical denial of service vulnerability in Linux kernel, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-64232 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-64232/ (Markdown: https://insights.sbomify.com/CVE-2026-64232/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64232
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64232
- OSV: https://osv.dev/vulnerability/CVE-2026-64232

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64232/
Summaries are generated and may contain mistakes; the official description above is the record.