Bug 2460693 (CVE-2026-31483)

Summary:	CVE-2026-31483 kernel: s390/syscalls: Add spectre boundary for syscall dispatch table
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in the Linux kernel's s390 architecture syscalls. A local attacker, by controlling the syscall number, could potentially access memory beyond the intended syscall function pointer tables. This lack of a boundary check, related to speculative execution (Spectre), may lead to information disclosure by allowing an attacker to read sensitive data from kernel memory.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-04-22 15:05:51 UTC

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

s390/syscalls: Add spectre boundary for syscall dispatch table

The s390 syscall number is directly controlled by userspace, but does
not have an array_index_nospec() boundary to prevent access past the
syscall function pointer tables.

Comment 1 Keith Grant 2026-04-22 18:44:17 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042259-CVE-2026-31483-9bc8@gregkh/T