CVE-2026-31482: s390/entry: Scrub r12 register on kernel entry

Published Apr 22, 2026
·
Updated

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

s390/entry: Scrub r12 register on kernel entry

Before commit f33f2d4c7c80 ("s390/bp: remove TIFISOLATEBP"), all entry handlers loaded r12 with the current task pointer (lg %r12,LCCURRENT) for use by the BPENTER/BPEXIT macros. That commit removed TIFISOLATEBP, dropping both the branch prediction macros and the r12 load, but did not add r12 to the register clearing sequence.

Add the missing xgr %r12,%r12 to make the register scrub consistent across all entry points.

Affected Software

168 affected componentsFixes available
Linux Linux kernel
Linux Linux kernel>=6.4.1<6.6.131
Linux Linux kernel>=6.7<6.12.80
Linux Linux kernel>=6.13<6.18.21
Linux Linux kernel>=6.19<6.19.11
Linux Linux kernel=6.4
Linux Linux kernel=7.0-rc1
Linux Linux kernel=7.0-rc2
Linux Linux kernel=7.0-rc3
Linux Linux kernel=7.0-rc4
Linux Linux kernel=7.0-rc5
Linux Linux kernel=7.0-rc6
Linux Linux kernel=7.0-rc7
debian/linux
6.1.176-16.1.190-16.12.107-16.12.115-27.2.12-17.2.15-1
ubuntu/linux-hwe-edge*
ubuntu/linux-aws-5.0*
ubuntu/linux-aws-5.3*
ubuntu/linux-azure*
ubuntu/linux-azure-5.3*
ubuntu/linux-azure-edge*
ubuntu/linux-gcp*
ubuntu/linux-gcp-5.3*
ubuntu/linux-gke-4.15*
ubuntu/linux-gke-5.4*
ubuntu/linux-gkeop-5.4*
ubuntu/linux-hwe*
ubuntu/linux-hwe-edge*
ubuntu/linux-oem*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-aws-5.11*
ubuntu/linux-aws-5.13*
ubuntu/linux-aws-5.8*
ubuntu/linux-azure-5.11*
ubuntu/linux-azure-5.13*
ubuntu/linux-azure-5.8*
ubuntu/linux-azure-fde*
ubuntu/linux-gcp-5.11*
ubuntu/linux-gcp-5.13*
ubuntu/linux-gcp-5.8*
ubuntu/linux-gke*
ubuntu/linux-gke-5.15*
ubuntu/linux-gkeop*
ubuntu/linux-gkeop-5.15*
ubuntu/linux-hwe-5.11*
ubuntu/linux-hwe-5.13*
ubuntu/linux-hwe-5.8*
ubuntu/linux-intel-5.13*
ubuntu/linux-oem-5.10*
ubuntu/linux-oem-5.13*
ubuntu/linux-oem-5.6*
ubuntu/linux-oracle-5.11*
ubuntu/linux-oracle-5.13*
ubuntu/linux-oracle-5.8*
ubuntu/linux-raspi2*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.11*
ubuntu/linux-riscv-5.8*
ubuntu/linux-allwinner-5.19*
ubuntu/linux-aws-5.19*
ubuntu/linux-aws-6.2*
ubuntu/linux-aws-6.5*
ubuntu/linux-aws-6.8<6.8.0-1061.64~22.04.1
6.8.0-1061.64~22.04.1
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-6.5*
ubuntu/linux-azure-6.8<6.8.0-1063.71~22.04.1
6.8.0-1063.71~22.04.1
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-azure-fde-6.8<6.8.0-1062.69~22.04.1
6.8.0-1062.69~22.04.1
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-gcp-6.5*
ubuntu/linux-gcp-6.8<6.8.0-1064.72~22.04.1
6.8.0-1064.72~22.04.1
ubuntu/linux-hwe-5.19*
ubuntu/linux-hwe-6.2*
ubuntu/linux-hwe-6.5*
ubuntu/linux-hwe-6.8<6.8.0-136.136~22.04.1
6.8.0-136.136~22.04.1
ubuntu/linux-ibm-6.8<6.8.0-1061.62~22.04.1
6.8.0-1061.62~22.04.1
ubuntu/linux-intel-iot-realtime*
ubuntu/linux-lowlatency-hwe-5.19*
ubuntu/linux-lowlatency-hwe-6.2*
ubuntu/linux-lowlatency-hwe-6.5*
ubuntu/linux-lowlatency-hwe-6.8<6.8.0-136.136.2~22.04.1
6.8.0-136.136.2~22.04.1
ubuntu/linux-nvidia-6.2*
ubuntu/linux-nvidia-6.5*
ubuntu/linux-nvidia-6.8<6.8.0-1059.62~22.04.1
6.8.0-1059.62~22.04.1
ubuntu/linux-oem-5.17*
ubuntu/linux-oem-6.0*
ubuntu/linux-oem-6.1*
ubuntu/linux-oem-6.5*
ubuntu/linux-oracle-6.5*
ubuntu/linux-oracle-6.8<6.8.0-1058.61~22.04.1
6.8.0-1058.61~22.04.1
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-riscv-6.5*
ubuntu/linux-riscv-6.8<6.8.0-136.136~22.04.3
6.8.0-136.136~22.04.3
ubuntu/linux-starfive-5.19*
ubuntu/linux-starfive-6.2*
ubuntu/linux-starfive-6.5*
ubuntu/linux-realtime-6.8<6.8.1-1056.57~22.04.2
6.8.1-1056.57~22.04.2
ubuntu/linux<6.8.0-136.136
6.8.0-136.136
ubuntu/linux-aws<6.8.0-1061.64
6.8.0-1061.64
ubuntu/linux-aws-6.14*
ubuntu/linux-aws-6.17*
ubuntu/linux-azure<6.8.0-1063.71
6.8.0-1063.71
ubuntu/linux-azure-6.11*
ubuntu/linux-azure-6.14*
ubuntu/linux-azure-6.17*
ubuntu/linux-azure-fde<6.8.0-1062.69
6.8.0-1062.69
ubuntu/linux-azure-fde-6.14*
ubuntu/linux-azure-nvidia*
ubuntu/linux-azure-nvidia-6.14*
ubuntu/linux-gcp<6.8.0-1064.72
6.8.0-1064.72
ubuntu/linux-gcp-6.11*
ubuntu/linux-gcp-6.14*
ubuntu/linux-gke<6.8.0-1059.67
6.8.0-1059.67
ubuntu/linux-gkeop<6.8.0-1046.50
6.8.0-1046.50
ubuntu/linux-hwe-6.11*
ubuntu/linux-hwe-6.14*
ubuntu/linux-hwe-6.17*
ubuntu/linux-ibm<6.8.0-1061.62
6.8.0-1061.62
ubuntu/linux-lowlatency<6.8.0-136.136.2
6.8.0-136.136.2
ubuntu/linux-lowlatency-hwe-6.11*
ubuntu/linux-nvidia<6.8.0-1059.62
6.8.0-1059.62
ubuntu/linux-nvidia-6.11*
ubuntu/linux-nvidia-6.17*
ubuntu/linux-nvidia-lowlatency<6.8.0-1059.62.1
6.8.0-1059.62.1
ubuntu/linux-nvidia-tegra<6.8.0-1030.31
6.8.0-1030.31
ubuntu/linux-oem-6.11*
ubuntu/linux-oem-6.14*
ubuntu/linux-oem-6.17*
ubuntu/linux-oem-6.8*
ubuntu/linux-oracle<6.8.0-1058.61
6.8.0-1058.61
ubuntu/linux-oracle-6.14*
ubuntu/linux-oracle-6.17*
ubuntu/linux-raspi<6.8.0-1061.65
6.8.0-1061.65
ubuntu/linux-raspi-realtime*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-6.14*
ubuntu/linux-riscv-6.17*
ubuntu/linux-xilinx<6.8.0-1033.34
6.8.0-1033.34
ubuntu/linux-bluefield<6.8.0-1028.33
6.8.0-1028.33
ubuntu/linux-raspi-realtime<6.8.0-2050.52
6.8.0-2050.52
ubuntu/linux-realtime<6.8.1-1056.57
6.8.1-1056.57
ubuntu/linux-realtime-6.14*
ubuntu/linux-realtime-6.17*
ubuntu/linux-aws-fips<6.8.0-1061.64+fips1
6.8.0-1061.64+fips1
ubuntu/linux-azure-fips<6.8.0-1063.71+fips2
6.8.0-1063.71+fips2
ubuntu/linux-fips<6.8.0-136.136+fips2
6.8.0-136.136+fips2
ubuntu/linux-gcp-fips<6.8.0-1064.72+fips1
6.8.0-1064.72+fips1
ubuntu/linux*
ubuntu/linux-aws*
ubuntu/linux-azure*
ubuntu/linux-azure-fde*
ubuntu/linux-gcp*
ubuntu/linux-oracle*
ubuntu/linux-raspi*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
linux/kernel>=6.4.0<6.6.131
6.6.131
linux/kernel>=6.7.0<6.12.80
6.12.80
linux/kernel>=6.13.0<6.18.21
6.18.21
linux/kernel>=6.19.0<6.19.11
6.19.11
debian/linux<6.12.85-1
6.12.85-1
debian/linux<6.19.11-1
6.19.11-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade debian/linux to a version that resolves this vulnerability.

    Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1
  2. Upgrade

    Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1061.64~22.04.1
  3. Upgrade

    Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1063.71~22.04.1
  4. Upgrade

    Upgrade ubuntu/linux-azure-fde-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1062.69~22.04.1
  5. Upgrade

    Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1064.72~22.04.1
  6. Upgrade

    Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-136.136~22.04.1
  7. Upgrade

    Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1061.62~22.04.1
  8. Upgrade

    Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-136.136.2~22.04.1
  9. Upgrade

    Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1059.62~22.04.1
  10. Upgrade

    Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1058.61~22.04.1
  11. Upgrade

    Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-136.136~22.04.3
  12. Upgrade

    Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.1-1056.57~22.04.2
  13. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 6.8.0-136.136
  14. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 6.8.0-1061.64
  15. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 6.8.0-1063.71
  16. Upgrade

    Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.

    Fixed in 6.8.0-1062.69
  17. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 6.8.0-1064.72
  18. Upgrade

    Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.

    Fixed in 6.8.0-1059.67
  19. Upgrade

    Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.

    Fixed in 6.8.0-1046.50
  20. Upgrade

    Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.

    Fixed in 6.8.0-1061.62
  21. Upgrade

    Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.

    Fixed in 6.8.0-136.136.2
  22. Upgrade

    Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.

    Fixed in 6.8.0-1059.62
  23. Upgrade

    Upgrade ubuntu/linux-nvidia-lowlatency to a version that resolves this vulnerability.

    Fixed in 6.8.0-1059.62.1
  24. Upgrade

    Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.

    Fixed in 6.8.0-1030.31
  25. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 6.8.0-1058.61
  26. Upgrade

    Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.

    Fixed in 6.8.0-1061.65
  27. Upgrade

    Upgrade ubuntu/linux-xilinx to a version that resolves this vulnerability.

    Fixed in 6.8.0-1033.34
  28. Upgrade

    Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.

    Fixed in 6.8.0-1028.33
  29. Upgrade

    Upgrade ubuntu/linux-raspi-realtime to a version that resolves this vulnerability.

    Fixed in 6.8.0-2050.52
  30. Upgrade

    Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.

    Fixed in 6.8.1-1056.57
  31. Upgrade

    Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.

    Fixed in 6.8.0-1061.64+fips1
  32. Upgrade

    Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.

    Fixed in 6.8.0-1063.71+fips2
  33. Upgrade

    Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.

    Fixed in 6.8.0-136.136+fips2
  34. Upgrade

    Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.

    Fixed in 6.8.0-1064.72+fips1
  35. Upgrade

    Upgrade linux/Kernel to a version that resolves this vulnerability.

    Fixed in 6.6.131
  36. Upgrade

    Upgrade linux/Kernel to a version that resolves this vulnerability.

    Fixed in 6.12.80
  37. Upgrade

    Upgrade linux/Kernel to a version that resolves this vulnerability.

    Fixed in 6.18.21
  38. Upgrade

    Upgrade linux/Kernel to a version that resolves this vulnerability.

    Fixed in 6.19.11
  39. Upgrade

    Upgrade debian/linux to a version that resolves this vulnerability.

    Fixed in 6.12.85-1
  40. Upgrade

    Upgrade debian/linux to a version that resolves this vulnerability.

    Fixed in 6.19.11-1

Event History

Apr 22, 2026
CVE Published
via MITRE·01:54 PM
Data Sourced
via MITRE·01:54 PM
Description
Data Sourced
via OSV·01:54 PM
DescriptionAffected Software
Data Sourced
via OSV·02:16 PM
Severity
Data Sourced
via NVD·02:16 PM
RemedyDescriptionSeverityAffected Software
Apr 23, 2026
Data Sourced
via Microsoft·08:06 AM
DescriptionSeverityWeakness

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

Which systems are affected?

The issue is in the Linux kernel s390 entry code, so it is relevant to systems running the Linux kernel on the s390 architecture. The supplied data also lists Debian's linux package.

2

What access does an attacker need?

The severity vector indicates local attack access and low privileges are required. No user interaction is required.

3

What is the impact described by the severity vector?

The vector indicates an availability impact rated high, with no confidentiality or integrity impact. The scope is unchanged.

4

What change addresses the issue?

The fix adds an xgr %r12,%r12 instruction to clear register r12 during kernel entry, making register scrubbing consistent across entry points.

Company

Resources

Contact

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