CVE-2025-40008: kmsan: fix out-of-bounds access to shadow memory

Published Oct 20, 2025
·
Updated

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

kmsan: fix out-of-bounds access to shadow memory

Running sha224kunit on a KMSAN-enabled kernel results in a crash in kmsaninternalsetshadoworigin():

BUG: unable to handle page fault for address: ffffbc3840291000 #PF: supervisor read access in kernel mode #PF: errorcode(0x0000) - not-present page PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 81 Comm: kunittrycatch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary) Tainted: [N]=TEST Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 RIP: 0010:kmsaninternalsetshadoworigin+0x91/0x100 [...] Call Trace: <TASK> msanmemset+0xee/0x1a0 sha224final+0x9e/0x350 testhashbufferoverruns+0x46f/0x5f0 ? kmsangetshadoworiginptr+0x46/0xa0 ? pfxtesthashbufferoverruns+0x10/0x10 kunittryruncase+0x198/0xa00

This occurs when memset() is called on a buffer that is not 4-byte aligned and extends to the end of a guard page, i.e. the next page is unmapped.

The bug is that the loop at the end of kmsaninternalsetshadoworigin() accesses the wrong shadow memory bytes when the address is not 4-byte aligned. Since each 4 bytes are associated with an origin, it rounds the address and size so that it can access all the origins that contain the buffer. However, when it checks the corresponding shadow bytes for a particular origin, it incorrectly uses the original unrounded shadow address. This results in reads from shadow memory beyond the end of the buffer's shadow memory, which crashes when that memory is not mapped.

To fix this, correctly align the shadow address before accessing the 4 shadow bytes corresponding to each origin.

Affected Software

142 affected componentsFixes available
Linux Linux kernel
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<6.8.0-1050.53~22.04.1
6.8.0-1050.53~22.04.1
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-6.5*
ubuntu/linux-azure-6.8<6.8.0-1051.57~22.04.1
6.8.0-1051.57~22.04.1
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-azure-fde-6.8<6.8.0-1058.65~22.04.1
6.8.0-1058.65~22.04.1
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-gcp-6.5*
ubuntu/linux-gcp-6.8<6.8.0-1052.55~22.04.1
6.8.0-1052.55~22.04.1
ubuntu/linux-hwe-5.19*
ubuntu/linux-hwe-6.2*
ubuntu/linux-hwe-6.5*
ubuntu/linux-hwe-6.8<6.8.0-106.106~22.04.1
6.8.0-106.106~22.04.1
ubuntu/linux-ibm-6.8<6.8.0-1049.49~22.04.1
6.8.0-1049.49~22.04.1
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<6.8.0-106.106.1~22.04.1
6.8.0-106.106.1~22.04.1
ubuntu/linux-nvidia-6.2*
ubuntu/linux-nvidia-6.5*
ubuntu/linux-nvidia-6.8<6.8.0-1049.52~22.04.1
6.8.0-1049.52~22.04.1
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<6.8.0-1047.48~22.04.1
6.8.0-1047.48~22.04.1
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-riscv-6.5*
ubuntu/linux-riscv-6.8<6.8.0-106.106~22.04.1
6.8.0-106.106~22.04.1
ubuntu/linux-starfive-5.19*
ubuntu/linux-starfive-6.2*
ubuntu/linux-starfive-6.5*
ubuntu/linux-realtime-6.8<6.8.1-1045.46~22.04.1
6.8.1-1045.46~22.04.1
ubuntu/linux<6.8.0-106.106
6.8.0-106.106
ubuntu/linux-aws<6.8.0-1050.53
6.8.0-1050.53
ubuntu/linux-aws-6.14*
ubuntu/linux-azure<6.8.0-1051.57
6.8.0-1051.57
ubuntu/linux-azure-6.11*
ubuntu/linux-azure-6.14*
ubuntu/linux-azure-fde<6.8.0-1058.65
6.8.0-1058.65
ubuntu/linux-azure-fde-6.14*
ubuntu/linux-azure-nvidia*
ubuntu/linux-azure-nvidia-6.14*
ubuntu/linux-gcp<6.8.0-1052.55
6.8.0-1052.55
ubuntu/linux-gcp-6.11*
ubuntu/linux-gcp-6.14*
ubuntu/linux-gke<6.8.0-1048.53
6.8.0-1048.53
ubuntu/linux-gkeop<6.8.0-1035.38
6.8.0-1035.38
ubuntu/linux-hwe-6.11*
ubuntu/linux-hwe-6.14*
ubuntu/linux-ibm<6.8.0-1049.49
6.8.0-1049.49
ubuntu/linux-lowlatency<6.8.0-106.106.1
6.8.0-106.106.1
ubuntu/linux-lowlatency-hwe-6.11*
ubuntu/linux-nvidia<6.8.0-1049.52
6.8.0-1049.52
ubuntu/linux-nvidia-6.11*
ubuntu/linux-nvidia-lowlatency<6.8.0-1049.52.1
6.8.0-1049.52.1
ubuntu/linux-nvidia-tegra<6.8.0-1020.20
6.8.0-1020.20
ubuntu/linux-oem-6.11*
ubuntu/linux-oem-6.14*
ubuntu/linux-oem-6.8*
ubuntu/linux-oracle<6.8.0-1047.48
6.8.0-1047.48
ubuntu/linux-oracle-6.14*
ubuntu/linux-raspi<6.8.0-1050.54
6.8.0-1050.54
ubuntu/linux-raspi-realtime*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-6.14*
ubuntu/linux-xilinx<6.8.0-1028.29
6.8.0-1028.29
ubuntu/linux-bluefield<6.8.0-1017.21
6.8.0-1017.21
ubuntu/linux-raspi-realtime<6.8.0-2040.41
6.8.0-2040.41
ubuntu/linux-realtime<6.8.1-1045.46
6.8.1-1045.46
ubuntu/linux-realtime-6.14*
ubuntu/linux-aws-fips<6.8.0-1050.53+fips1
6.8.0-1050.53+fips1
ubuntu/linux-azure-fips<6.8.0-1052.58+fips1
6.8.0-1052.58+fips1
ubuntu/linux-fips<6.8.0-106.106+fips1
6.8.0-106.106+fips1
ubuntu/linux-gcp-fips<6.8.0-1052.55+fips1
6.8.0-1052.55+fips1
ubuntu/linux<6.17.0-6.6
6.17.0-6.6
ubuntu/linux-aws<6.17.0-1003.3
6.17.0-1003.3
ubuntu/linux-azure<6.17.0-1006.6
6.17.0-1006.6
ubuntu/linux-azure-fde*
ubuntu/linux-gcp<6.17.0-1003.3
6.17.0-1003.3
ubuntu/linux-oracle<6.17.0-1003.3
6.17.0-1003.3
ubuntu/linux-raspi<6.17.0-1004.4
6.17.0-1004.4
ubuntu/linux-realtime<6.17.0-1002.3
6.17.0-1002.3
ubuntu/linux-riscv<6.17.0-6.6.1
6.17.0-6.6.1
debian/linux
6.1.176-16.1.190-16.12.107-16.12.115-27.2.15-17.3.3-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

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

    Fixed in 6.8.0-1050.53~22.04.1
  2. Upgrade

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

    Fixed in 6.8.0-1051.57~22.04.1
  3. Upgrade

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

    Fixed in 6.8.0-1058.65~22.04.1
  4. Upgrade

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

    Fixed in 6.8.0-1052.55~22.04.1
  5. Upgrade

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

    Fixed in 6.8.0-106.106~22.04.1
  6. Upgrade

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

    Fixed in 6.8.0-1049.49~22.04.1
  7. Upgrade

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

    Fixed in 6.8.0-106.106.1~22.04.1
  8. Upgrade

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

    Fixed in 6.8.0-1049.52~22.04.1
  9. Upgrade

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

    Fixed in 6.8.0-1047.48~22.04.1
  10. Upgrade

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

    Fixed in 6.8.0-106.106~22.04.1
  11. Upgrade

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

    Fixed in 6.8.1-1045.46~22.04.1
  12. Upgrade

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

    Fixed in 6.8.0-106.106
  13. Upgrade

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

    Fixed in 6.8.0-1050.53
  14. Upgrade

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

    Fixed in 6.8.0-1051.57
  15. Upgrade

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

    Fixed in 6.8.0-1058.65
  16. Upgrade

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

    Fixed in 6.8.0-1052.55
  17. Upgrade

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

    Fixed in 6.8.0-1048.53
  18. Upgrade

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

    Fixed in 6.8.0-1035.38
  19. Upgrade

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

    Fixed in 6.8.0-1049.49
  20. Upgrade

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

    Fixed in 6.8.0-106.106.1
  21. Upgrade

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

    Fixed in 6.8.0-1049.52
  22. Upgrade

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

    Fixed in 6.8.0-1049.52.1
  23. Upgrade

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

    Fixed in 6.8.0-1020.20
  24. Upgrade

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

    Fixed in 6.8.0-1047.48
  25. Upgrade

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

    Fixed in 6.8.0-1050.54
  26. Upgrade

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

    Fixed in 6.8.0-1028.29
  27. Upgrade

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

    Fixed in 6.8.0-1017.21
  28. Upgrade

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

    Fixed in 6.8.0-2040.41
  29. Upgrade

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

    Fixed in 6.8.1-1045.46
  30. Upgrade

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

    Fixed in 6.8.0-1050.53+fips1
  31. Upgrade

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

    Fixed in 6.8.0-1052.58+fips1
  32. Upgrade

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

    Fixed in 6.8.0-106.106+fips1
  33. Upgrade

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

    Fixed in 6.8.0-1052.55+fips1
  34. Upgrade

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

    Fixed in 6.17.0-6.6
  35. Upgrade

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

    Fixed in 6.17.0-1003.3
  36. Upgrade

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

    Fixed in 6.17.0-1006.6
  37. Upgrade

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

    Fixed in 6.17.0-1003.3
  38. Upgrade

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

    Fixed in 6.17.0-1003.3
  39. Upgrade

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

    Fixed in 6.17.0-1004.4
  40. Upgrade

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

    Fixed in 6.17.0-1002.3
  41. Upgrade

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

    Fixed in 6.17.0-6.6.1
  42. 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 7.2.15-1Fixed in 7.3.3-1

Event History

Oct 20, 2025
CVE Published
via MITRE·03:26 PM
Data Sourced
via MITRE·03:26 PM
Description
Data Sourced
via OSV·04:15 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·04:15 PM
Description

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

What is the severity of CVE-2025-40008?

CVE-2025-40008 has a high severity level due to the potential for crashes related to out-of-bounds access in the Linux kernel.

2

How do I fix CVE-2025-40008?

To fix CVE-2025-40008, update to a patched version of the Linux kernel where the vulnerability has been resolved.

3

What software is affected by CVE-2025-40008?

CVE-2025-40008 affects KMSAN-enabled versions of the Linux kernel.

4

What types of exploitation are possible with CVE-2025-40008?

Exploitation of CVE-2025-40008 may lead to a system crash when executing certain operations like running sha224_kunit.

5

Is there a workaround for CVE-2025-40008?

There is no official workaround for CVE-2025-40008; the recommended action is to apply the necessary kernel updates.

Company

Resources

Contact

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