CVE-2026-98476
Received Received - Intake

NULL Pointer Dereference in Linux Kernel s390/cio

Publication date: 2026-10-18

Last updated on: 2026-10-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: s390/cio: Fix NULL pointer dereference in ccw_device_get_util_str() The channel path registry entry associated with a CHPID may be removed while the subchannel's PMCW still references that CHPID. In this case, chpid_to_chp() can return NULL, leading to a NULL pointer dereference. Add the missing NULL check before dereferencing the returned pointer.

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Meta Information

Published
2026-10-18
Last Modified
2026-10-18
Generated
2026-10-18
AI Q&A
2026-10-18
EPSS Evaluated
N/A
NVD
CVE-2026-98476
EUVD
EUVD-2026-103716

Affected Vendors & Products

Showing 9 associated CPEs
Vendor Product Version / Range
Linux Linux 199652309a4d6635fca19d7528d73ab9e219bd9a
Linux Linux 199652309a4d6635fca19d7528d73ab9e219bd9a
Linux Linux 199652309a4d6635fca19d7528d73ab9e219bd9a
Linux Linux 199652309a4d6635fca19d7528d73ab9e219bd9a
Linux Linux 199652309a4d6635fca19d7528d73ab9e219bd9a
Linux Linux 199652309a4d6635fca19d7528d73ab9e219bd9a
Linux Linux 199652309a4d6635fca19d7528d73ab9e219bd9a
Linux Linux 199652309a4d6635fca19d7528d73ab9e219bd9a
Linux Linux 4.18

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a Linux kernel vulnerability where a NULL pointer dereference flaw exists in the s390/cio component. It occurs when a channel path registry entry is removed while a subchannel still references it, causing chpid_to_chp() to return NULL. Without a proper check, this leads to a crash when the returned pointer is dereferenced.

Detection Guidance

This vulnerability is specific to the Linux kernel's s390/cio component and involves a NULL pointer dereference in ccw_device_get_util_str(). Detection requires checking the kernel version and examining the s390/cio subsystem for the described race condition. No direct commands are provided in the context, but monitoring kernel logs for NULL pointer dereference errors in the s390/cio module may help identify exploitation attempts.

Impact Analysis

This vulnerability can cause system crashes or instability on affected Linux systems using the s390 architecture. It may lead to denial-of-service conditions if exploited, potentially disrupting services running on the vulnerable system.

Mitigation Strategies

Apply the latest kernel update that includes the fix for this vulnerability. If immediate patching is not possible, consider disabling or restricting access to the affected s390/cio subsystem if it is not critical for your operations. Monitor vendor advisories for updates and test the patch in a non-production environment before full deployment.

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