What is CVE-2021-47439?

CVE-2021-47439 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, classified as a NULL Pointer Dereference flaw (CWE-476), affecting Linux kernel versions from 5.7 onward and patched in 5.10.75, 5.14.14 and 5.15. CVE-2021-47439 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-47439?

CVE-2021-47439 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2021-47439?

Yes, CVE-2021-47439 has been patched. Fixed versions include 5.10.75, 5.14.14 and 5.15. If you are running Linux kernel 5.7 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2021-47439 actively exploited?

CVE-2021-47439 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-2021-47439

Medium

In the Linux kernel, the following vulnerability has been resolved: net: dsa: microchip: Added the condition for scheduling ksz_mib_read_work When the ksz module is installed and removed using rmmod, kernel crashes with null pointer dereferrence error. During rmmod, ksz_switch_remove function tries to cancel the mib_read_workqueue using cancel_delayed_work_sync routine and unregister switch from dsa. During dsa_unregister_switch it calls ksz_mac_link_down, which in turn reschedules the workqueue since mib_interval is non-zero. Due to which queue executed after mib_interval and it tries to access dp->slave. But the slave is unregistered in the ksz_switch_remove function. Hence kernel crashes. To avoid this crash, before canceling the workqueue, resetted the mib_interval to 0. v1 -> v2: -Removed the if condition in ksz_mib_read_work

Package Linux Kernel

Published 2024-05-22

Last modified 2025-04-02

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Weakness type

CWE-476

CVE-2021-47439 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 5.7 and later are affected. Fixed in 5.10.75, 5.14.14, 5.15 and their respective stable series.

Affected from

≥ 5.7

Fixed in

✓ 5.10.75 5.10.x ✓ 5.14.14 5.14.x ✓ 5.15

References

3 total

Kernel Git
https://git.kernel.org/stable/c/383239a33cf29ebee9ce0d4e0e5c900b77a16148

Patch
Kernel Git
https://git.kernel.org/stable/c/ef1100ef20f29aec4e62abeccdb5bdbebba1e378

Patch
Kernel Git
https://git.kernel.org/stable/c/f2e1de075018cf71bcd7d628e9f759cb8540b0c3

Patch

Details

CVE ID CVE-2021-47439

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2024-05-22

Modified 2025-04-02

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2021-47439?

CVE-2021-47439 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a NULL Pointer Dereference flaw (CWE-476) . It affects Linux kernel versions from 5.7 onward and has been patched in 5.10.75, 5.14.14 and 5.15. CVE-2021-47439 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-47439?

CVE-2021-47439 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2021-47439?

Yes. CVE-2021-47439 has been patched. Fixed versions include 5.10.75, 5.14.14 and 5.15. If you are running Linux kernel 5.7 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2021-47439 actively exploited?

No. CVE-2021-47439 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.