CVE-2026-31483

Service interruption via speculative syscall dispatch

Published Apr 22, 2026 · Updated Apr 22, 2026

Speculative execution in affected Linux Kernel releases on s390 allows local users to interrupt service via crafted syscall numbers. The s390 syscall dispatcher uses a userspace-controlled index without array_index_nospec(), permitting speculative access past function-pointer tables. Low-privileged local execution on s390 is required; published evidence supports service interruption but not data access or modification.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Speculative execution in affected Linux Kernel releases on s390 allows local users to interrupt service via crafted syscall numbers. The s390 syscall dispatcher uses a userspace-controlled index without array_index_nospec(), permitting speculative access past function-pointer tables. Low-privileged local execution on s390 is required; published evidence supports service interruption but not data access or modification.

The record

CVE
CVE-2026-31483
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.12
  2. Affected versionversion=56e62a73702836017564eaacd5212e4d0fa1c01d <1cb9c7bc9025c637564fabc7fcc3c9343949e310
  3. Affected versionversion=56e62a73702836017564eaacd5212e4d0fa1c01d <3c3b97064764899c39a0abbd35a6caa031e70333
  4. Affected versionversion=56e62a73702836017564eaacd5212e4d0fa1c01d <48b8814e25d073dd84daf990a879a820bad2bcbd
  5. Affected versionversion=56e62a73702836017564eaacd5212e4d0fa1c01d <4d05dd18d867d58c6952a3bc260d244899da7256
  6. Affected versionversion=56e62a73702836017564eaacd5212e4d0fa1c01d <7a5260fbc6e79a1595328ec5c6aa3f937504a1f0
  7. Affected versionversion=56e62a73702836017564eaacd5212e4d0fa1c01d <87776f02449e3bded95b2ccbd6b012e9ae64e6f3
  8. Affected versionversion=56e62a73702836017564eaacd5212e4d0fa1c01d <f8c444b918d639e1f9a621ee20fe481c1d10dfc4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.12; version=56e62a73702836017564eaacd5212e4d0fa1c01d <1cb9c7bc9025c637564fabc7fcc3c9343949e310; version=56e62a73702836017564eaacd5212e4d0fa1c01d <3c3b97064764899c39a0abbd35a6caa031e70333; version=56e62a73702836017564eaacd5212e4d0fa1c01d <48b8814e25d073dd84daf990a879a820bad2bcbd; version=56e62a73702836017564eaacd5212e4d0fa1c01d <4d05dd18d867d58c6952a3bc260d244899da7256; version=56e62a73702836017564eaacd5212e4d0fa1c01d <7a5260fbc6e79a1595328ec5c6aa3f937504a1f0; version=56e62a73702836017564eaacd5212e4d0fa1c01d <87776f02449e3bded95b2ccbd6b012e9ae64e6f3; version=56e62a73702836017564eaacd5212e4d0fa1c01d <f8c444b918d639e1f9a621ee20fe481c1d10dfc4

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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