Bug 2493774 (CVE-2026-53282)

Summary: CVE-2026-53282 kernel: x86/kexec: Push kjump return address even for non-kjump kexec
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's kexec functionality, specifically within the purgatory code used by kexec-tools. This vulnerability occurs when the purgatory code attempts to locate a return address on the stack during a non-kjump kexec operation, but the address is not present. This can lead to a system fault or crash, impacting system availability.
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Description OSIDB Bzimport 2026-06-26 21:06:52 UTC 
In the Linux kernel, the following vulnerability has been resolved:

x86/kexec: Push kjump return address even for non-kjump kexec

The version of purgatory code shipped by kexec-tools attempts to look above
the top of its stack to find a return address for a kjump, even in a non-kjump
kexec.

After the commit in Fixes: the word above the stack might not be there,
leading to a fault (which is at least now caught by my exception-handling code
in kexec).

That commit fixed things for the actual kjump path, but no longer
"gratuitously" pushes the unused return address to the stack in the non-kjump
path. Put that *back* in the non-kjump path, to prevent purgatory from
crashing when trying to access it.
Comment 1 Mauro Matteo Cascella 2026-06-29 08:02:24 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062615-CVE-2026-53282-2ffa@gregkh/T