Bug 2535378 (CVE-2026-89963)

Summary:	CVE-2026-89963 kernel: powerpc/kexec_file: Fix null-ptr-def in extra size calculation
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in the Linux kernel's `powerpc/kexec_file` component. On systems configured without reserved memory regions, a NULL pointer dereference can occur in the `kexec_extra_fdt_size_ppc64()` function during extra size calculation. This can lead to a kernel panic, effectively causing a denial of service (DoS) for the affected system.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-16 12:26:39 UTC

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

powerpc/kexec_file: Fix null-ptr-def in extra size calculation

A static Sashiko AI review identified a potential NULL pointer
dereference in kexec_extra_fdt_size_ppc64().

On platforms without any reserved memory regions,
get_reserved_memory_ranges() can return 0 while leaving 'rmem'
unallocated as NULL. Passing it directly leads to a kernel panic when
evaluating 'rmem->nr_ranges'.

Add a NULL check for 'rmem' to prevent this crash.

Comment 1 Mauro Matteo Cascella 2026-09-17 15:45:03 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89963.mbox