What is CVE-2021-47281?

CVE-2021-47281 is a High severity Linux kernel vulnerability with a CVSS score of 7.0 out of 10, classified as a Use After Free flaw (CWE-416), affecting Linux kernel versions from 2.6.12 onward and patched in 5.10.44, 5.12.11 and 5.13. CVE-2021-47281 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-47281?

CVE-2021-47281 has a CVSS score of 7.0 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2021-47281?

Yes, CVE-2021-47281 has been patched. Fixed versions include 5.10.44, 5.12.11 and 5.13. 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-2021-47281 actively exploited?

CVE-2021-47281 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Use After Free (CWE-416)?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/416.html

CVE-2021-47281

High

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix race of snd_seq_timer_open() The timer instance per queue is exclusive, and snd_seq_timer_open() should have managed the concurrent accesses. It looks as if it's checking the already existing timer instance at the beginning, but it's not right, because there is no protection, hence any later concurrent call of snd_seq_timer_open() may override the timer instance easily. This may result in UAF, as the leftover timer instance can keep running while the queue itself gets closed, as spotted by syzkaller recently. For avoiding the race, add a proper check at the assignment of tmr->timeri again, and return -EBUSY if it's been already registered.

Package Linux Kernel

Published 2024-05-21

Last modified 2024-12-24

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.0

out of 10

High

Attack Vector

Local

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Weakness type

CWE-416

CVE-2021-47281 is a Use After Free vulnerability

What is Use After Free?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. Learn more on MITRE CWE

Affected versions

Linux kernel versions 2.6.12 and later are affected. Fixed in 5.10.44, 5.12.11, 5.13 and their respective stable series.

Affected from

≥ 2.6.12

Fixed in

✓ 5.10.44 5.10.x ✓ 5.12.11 5.12.x ✓ 5.13

References

3 total

Kernel Git
https://git.kernel.org/stable/c/536a7646c00a0f14fee49e5e313109e5da2f6031

Patch
Kernel Git
https://git.kernel.org/stable/c/83e197a8414c0ba545e7e3916ce05f836f349273

Patch
Kernel Git
https://git.kernel.org/stable/c/bd7d88b0874f82f7b29d1a53e574cedaf23166ba

Patch

Details

CVE ID CVE-2021-47281

Severity High

CVSS score 7.0 / 10

CVSS version 3.1

Published 2024-05-21

Modified 2024-12-24

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2021-47281?

CVE-2021-47281 is a High severity Linux kernel vulnerability with a CVSS score of 7.0 out of 10 , classified as an Use After Free flaw (CWE-416) . It affects Linux kernel versions from 2.6.12 onward and has been patched in 5.10.44, 5.12.11 and 5.13. CVE-2021-47281 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-47281?

CVE-2021-47281 has a CVSS score of 7.0 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2021-47281?

Yes. CVE-2021-47281 has been patched. Fixed versions include 5.10.44, 5.12.11 and 5.13. 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-2021-47281 actively exploited?

No. CVE-2021-47281 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.