What is CVE-2021-47556?

CVE-2021-47556 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 5.15 onward and patched in 5.15.6 and 5.16. CVE-2021-47556 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-47556?

CVE-2021-47556 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-2021-47556?

Yes, CVE-2021-47556 has been patched. Fixed versions include 5.15.6 and 5.16. If you are running Linux kernel 5.15 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2021-47556 actively exploited?

CVE-2021-47556 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-2021-47556

Medium

In the Linux kernel, the following vulnerability has been resolved: ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce() ethtool_set_coalesce() now uses both the .get_coalesce() and .set_coalesce() callbacks. But the check for their availability is buggy, so changing the coalesce settings on a device where the driver provides only _one_ of the callbacks results in a NULL pointer dereference instead of an -EOPNOTSUPP. Fix the condition so that the availability of both callbacks is ensured. This also matches the netlink code. Note that reproducing this requires some effort - it only affects the legacy ioctl path, and needs a specific combination of driver options: - have .get_coalesce() and .coalesce_supported but no .set_coalesce(), or - have .set_coalesce() but no .get_coalesce(). Here eg. ethtool doesn't cause the crash as it first attempts to call ethtool_get_coalesce() and bails out on error.

Package Linux Kernel

Published 2024-05-24

Last modified 2024-11-21

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-2021-47556 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 5.15 and later are affected. Fixed in 5.15.6, 5.16 and their respective stable series.

Affected from

≥ 5.15

Fixed in

✓ 5.15.6 5.15.x ✓ 5.16

References

2 total

Kernel Git
https://git.kernel.org/stable/c/0276af2176c78771da7f311621a25d7608045827

Patch
Kernel Git
https://git.kernel.org/stable/c/abfdd9e2f0f9699015d72317f74154d3e53664e6

Patch

Details

CVE ID CVE-2021-47556

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2024-05-24

Modified 2024-11-21

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2021-47556?

CVE-2021-47556 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 5.15 onward and has been patched in 5.15.6 and 5.16. CVE-2021-47556 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-47556?

CVE-2021-47556 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-2021-47556?

Yes. CVE-2021-47556 has been patched. Fixed versions include 5.15.6 and 5.16. If you are running Linux kernel 5.15 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2021-47556 actively exploited?

No. CVE-2021-47556 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.