CVE-2026-31483

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.

The upstream patch adds array_index_nospec() guarding on s390 syscall dispatch, closing speculative out-of-table reads. Red Hat treats this as architecture-specific Spectre hardening. Customers should consume updated s390 kernels; no discrete module unload applies.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.