---
id: "CVE-2026-98634"
kind: "vulnerability"
aliases: ["CVE-2026-98634"]
title: "Linux kernel: SCSI zoned disks with too many zones mishandled"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "linux-kernel", "scsi", "zoned-storage"]
not_affected_if: ["no-zoned-scsi-disks"]
published_at: "2026-10-18T16:17:16+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:21:00+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98634", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux kernel: SCSI zoned disks with too many zones mishandled

The Linux SCSI zoned-block code computes zone counts in 64-bit but stores them in 32-bit fields, and a signed counter overflows past INT_MAX. The fix rejects such disks at scan time, so a device reporting an enormous zone count is refused rather than causing inconsistent bookkeeping.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- Update the Linux kernel to a release that includes the sd_zbc fix (the sources do not name a version).

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98634

## From the sources

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

scsi: sd_zbc: Reject disks with too many zones

sd_zbc_read_zones() computes the number of zones with 64-bit arithmetic and
stores the result in the unsigned int nr_zones field of struct
zoned_disk_info, silently truncating counts that exceed 32 bits. The
truncated count is later used to size per-zone resources, while the device
may still report more zones than fit.

Moreover, sd_zbc_report_zones() counts the reported zones with a signed int
zone_idx, which overflows past INT_MAX. Reject devices reporting more than
INT_MAX zones at scan time; such a device is not realistic for any medium
that exists today, and accepting it produces inconsistent zone bookkeeping.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_