---
id: "CVE-2026-98593"
kind: "vulnerability"
aliases: ["CVE-2026-98593"]
title: "Linux kernel s390 debug facility: NULL pointer dereference crashes the kernel"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["linux-kernel", "mainframe", "runtime", "s390"]
not_affected_if: ["non-s390-hardware"]
published_at: "2026-10-18T16:17:11+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:21:40+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98593", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux kernel s390 debug facility: NULL pointer dereference crashes the kernel

When a static debug area fails to register on IBM s390 systems, the kernel leaves its area bounds set while clearing the pointers. Opening the debug view file or running debug_dump() then dereferences those NULL pointers and can crash the machine.

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

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98593

## From the sources

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

s390/debug: Fix NULL pointer dereference in debug_info_copy()

When debug_register_static() fails, it clears areas, active_pages and
active_entries but leaves the area bounds unchanged. Copying such an
area, either by opening its view file or via debug_dump(), makes
debug_info_copy() dereference the NULL pointers.

Skip the copy loop when the source has no areas.

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