CVE-2026-98635

Received Received - Intake

Linux Kernel Zone Report Out-of-Bounds Write

Publication date: 2026-10-18

Last updated on: 2026-10-19

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: scsi: block: Fix zones_cond out-of-bounds write on zone report blk_revalidate_disk_zones() sizes the zones_cond array from the disk capacity and zone size, but the index used by blk_revalidate_zone_cond() comes from the device-driven report_zones() walk and is never checked against the array size. A device reporting more zones than fit the array makes blk_zone_set_cond() write out of bounds. One way to reach this is a zone count exceeding 32 bits: both blk_revalidate_zone_args.nr_zones and struct zoned_disk_info.nr_zones are unsigned int, so a disk advertising more than UINT_MAX zones (e.g. 2^32 + 1024 zones of one 512-byte logical block) gets its zone count truncated to a small value, undersizing the array while the report walk keeps counting upward. Check the index against the array size before storing the zone condition, and refuse to revalidate when the zone count does not fit 32 bits.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-18

Last Modified

2026-10-19

Generated

2026-10-19

AI Q&A

2026-10-18

EPSS Evaluated

N/A

NVD

CVE-2026-98635

EUVD

EUVD-2026-103549

Affected Vendors & Products

Vendor	Product	Version / Range
Linux	Linux	6e945ffb6555705cf20b1fcdc21a139911562995
Linux	Linux	6e945ffb6555705cf20b1fcdc21a139911562995
Linux	Linux	6.19

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a vulnerability in the Linux kernel where a function called blk_revalidate_disk_zones() incorrectly sizes an array based on disk capacity and zone size. The issue occurs because the index used to write to this array comes from a device-driven report_zones() walk and is not checked against the array size. This can lead to an out-of-bounds write when the device reports more zones than the array can hold.

Detection Guidance

This vulnerability is specific to the Linux kernel's SCSI block layer and zone handling. Detection requires checking the kernel version and examining zone-related configurations on storage devices. Commands like 'uname -a' to check kernel version and 'lsblk -D' to inspect disk zone characteristics may help identify affected systems.

Impact Analysis

This vulnerability could allow an attacker with access to a vulnerable system to cause memory corruption, potentially leading to system crashes, privilege escalation, or arbitrary code execution. It may also result in data corruption or denial of service if exploited.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR or HIPAA as it pertains to a low-level Linux kernel issue involving out-of-bounds memory writes in SCSI block device handling. Compliance impacts would depend on system configuration and data exposure, not the vulnerability itself.

Mitigation Strategies

Apply the latest Linux kernel patches addressing this issue. Update the kernel to a version containing the fix for CVE-2026-98635. Monitor vendor advisories for storage device firmware updates if zone handling is used.

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