What is CVE-2021-47509?

CVE-2021-47509 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 2.6.12 onward and patched in 4.4.295, 4.9.293, 4.14.258 and others. CVE-2021-47509 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-47509?

CVE-2021-47509 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-2021-47509?

Yes, CVE-2021-47509 has been patched. Fixed versions include 4.4.295, 4.9.293, 4.14.258 and others. If you are running Linux kernel 2.6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2021-47509 actively exploited?

CVE-2021-47509 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2021-47509

Medium

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: oss: Limit the period size to 16MB Set the practical limit to the period size (the fragment shift in OSS) instead of a full 31bit; a too large value could lead to the exhaust of memory as we allocate temporary buffers of the period size, too. As of this patch, we set to 16MB limit, which should cover all use cases.

Package Linux Kernel

Published 2024-05-24

Last modified 2025-09-29

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

Affected versions

Linux kernel versions 2.6.12 and later are affected. Fixed in 4.4.295, 4.9.293, 4.14.258, 4.19.221, 5.4.165, 5.10.85, 5.15.8, 5.16 and their respective stable series.

Affected from

≥ 2.6.12

Fixed in

✓ 4.4.295 4.4.x ✓ 4.9.293 4.9.x ✓ 4.14.258 4.14.x ✓ 4.19.221 4.19.x ✓ 5.4.165 5.4.x ✓ 5.10.85 5.10.x ✓ 5.15.8 5.15.x ✓ 5.16

References

8 total

Kernel Git
https://git.kernel.org/stable/c/2e54cf6794bf82a54aaefc78da13819aea9cd28a

Patch
Kernel Git
https://git.kernel.org/stable/c/35a3e511032146941085f87dd9fb5b82ea5c00a2

Patch
Kernel Git
https://git.kernel.org/stable/c/76f19e4cbb548e28547f8c328aa0bfb3a10222d3

Patch
Kernel Git
https://git.kernel.org/stable/c/8839c8c0f77ab8fc0463f4ab8b37fca3f70677c2

Patch
Kernel Git
https://git.kernel.org/stable/c/ad45babf7886e7a212ee1d5eda9ef49f696db43c

Patch

Showing 5 of 8 references View all on NVD

Details

CVE ID CVE-2021-47509

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2024-05-24

Modified 2025-09-29

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2021-47509?

CVE-2021-47509 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 2.6.12 onward and has been patched in 4.4.295, 4.9.293, 4.14.258 and others. CVE-2021-47509 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-47509?

CVE-2021-47509 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-2021-47509?

Yes. CVE-2021-47509 has been patched. Fixed versions include 4.4.295, 4.9.293, 4.14.258 and others. If you are running Linux kernel 2.6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2021-47509 actively exploited?

No. CVE-2021-47509 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.