What is CVE-2021-47140?

CVE-2021-47140 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.3 out of 10, classified as a NULL Pointer Dereference flaw (CWE-476), affecting Linux kernel versions from 5.11 onward and patched in 5.12.9 and 5.13. CVE-2021-47140 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-47140?

CVE-2021-47140 has a CVSS score of 5.3 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Is there a patch available for CVE-2021-47140?

Yes, CVE-2021-47140 has been patched. Fixed versions include 5.12.9 and 5.13. If you are running Linux kernel 5.11 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2021-47140 actively exploited?

CVE-2021-47140 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is NULL Pointer Dereference (CWE-476)?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/476.html

CVE-2021-47140

Medium

In the Linux kernel, the following vulnerability has been resolved: iommu/amd: Clear DMA ops when switching domain Since commit 08a27c1c3ecf ("iommu: Add support to change default domain of an iommu group") a user can switch a device between IOMMU and direct DMA through sysfs. This doesn't work for AMD IOMMU at the moment because dev->dma_ops is not cleared when switching from a DMA to an identity IOMMU domain. The DMA layer thus attempts to use the dma-iommu ops on an identity domain, causing an oops: # echo 0000:00:05.0 > /sys/sys/bus/pci/drivers/e1000e/unbind # echo identity > /sys/bus/pci/devices/0000:00:05.0/iommu_group/type # echo 0000:00:05.0 > /sys/sys/bus/pci/drivers/e1000e/bind ... BUG: kernel NULL pointer dereference, address: 0000000000000028 ... Call Trace: iommu_dma_alloc e1000e_setup_tx_resources e1000e_open Since iommu_change_dev_def_domain() calls probe_finalize() again, clear the dma_ops there like Vt-d does.

Package Linux Kernel

Published 2024-03-25

Last modified 2025-03-19

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.3

out of 10

Medium

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

Low

Vector string

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Weakness type

CWE-476

CVE-2021-47140 is a NULL Pointer Dereference vulnerability

What is NULL Pointer Dereference?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. Learn more on MITRE CWE

Affected versions

Linux kernel versions 5.11 and later are affected. Fixed in 5.12.9, 5.13 and their respective stable series.

Affected from

≥ 5.11

Fixed in

✓ 5.12.9 5.12.x ✓ 5.13

References

2 total

Kernel Git
https://git.kernel.org/stable/c/d6177a6556f853785867e2ec6d5b7f4906f0d809

Patch
Kernel Git
https://git.kernel.org/stable/c/f3f2cf46291a693eab21adb94171b0128c2a9ec1

Patch

Details

CVE ID CVE-2021-47140

Severity Medium

CVSS score 5.3 / 10

CVSS version 3.1

Published 2024-03-25

Modified 2025-03-19

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2021-47140?

CVE-2021-47140 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.3 out of 10 , classified as a NULL Pointer Dereference flaw (CWE-476) . It affects Linux kernel versions from 5.11 onward and has been patched in 5.12.9 and 5.13. CVE-2021-47140 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-47140?

CVE-2021-47140 has a CVSS score of 5.3 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
Is there a patch available for CVE-2021-47140?

Yes. CVE-2021-47140 has been patched. Fixed versions include 5.12.9 and 5.13. If you are running Linux kernel 5.11 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2021-47140 actively exploited?

No. CVE-2021-47140 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.