CVE-2026-31482

Local service interruption via uncleared entry register

Published Apr 22, 2026 · Updated Apr 22, 2026

Improper register clearing in Linux kernel 6.4 and affected later s390 branches allows local users to interrupt service via kernel entry. The s390 entry handlers stopped loading r12 after TIF_ISOLATE_BP was removed, but the clearing sequence also failed to zero that register. Exploitation requires low-privileged local execution on an s390 system, and the published impact is limited to availability.

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

Improper register clearing in Linux kernel 6.4 and affected later s390 branches allows local users to interrupt service via kernel entry. The s390 entry handlers stopped loading r12 after TIF_ISOLATE_BP was removed, but the clearing sequence also failed to zero that register. Exploitation requires low-privileged local execution on an s390 system, and the published impact is limited to availability.

The record

CVE
CVE-2026-31482
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
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=6.4
  2. Affected versionversion=f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780 <0738d395aab8fae3b5a3ad3fc640630c91693c27
  3. Affected versionversion=f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780 <7f4e3233faa8470dd0627bc49b2809f2bfebd909
  4. Affected versionversion=f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780 <95c899cd791803a5bf7b73e5994fbbe1cc1a9c36
  5. Affected versionversion=f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780 <99a8b420f3f0e162eb9c9c9253929d4d23f9bd30
  6. Affected versionversion=f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780 <a58d298a83a3a9b7ca99ded9d60a1e77231159ef

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.4; version=f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780 <0738d395aab8fae3b5a3ad3fc640630c91693c27; version=f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780 <7f4e3233faa8470dd0627bc49b2809f2bfebd909; version=f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780 <95c899cd791803a5bf7b73e5994fbbe1cc1a9c36; version=f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780 <99a8b420f3f0e162eb9c9c9253929d4d23f9bd30; version=f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780 <a58d298a83a3a9b7ca99ded9d60a1e77231159ef

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

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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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

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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