What is CVE-2021-46904?

CVE-2021-46904 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 2.6.27 onward and patched in 4.4.268, 4.9.268, 4.14.232 and others. CVE-2021-46904 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-46904?

CVE-2021-46904 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-2021-46904?

Yes, CVE-2021-46904 has been patched. Fixed versions include 4.4.268, 4.9.268, 4.14.232 and others. If you are running Linux kernel 2.6.27 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2021-46904 actively exploited?

CVE-2021-46904 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-2021-46904

Medium

In the Linux kernel, the following vulnerability has been resolved: net: hso: fix null-ptr-deref during tty device unregistration Multiple ttys try to claim the same the minor number causing a double unregistration of the same device. The first unregistration succeeds but the next one results in a null-ptr-deref. The get_free_serial_index() function returns an available minor number but doesn't assign it immediately. The assignment is done by the caller later. But before this assignment, calls to get_free_serial_index() would return the same minor number. Fix this by modifying get_free_serial_index to assign the minor number immediately after one is found to be and rename it to obtain_minor() to better reflect what it does. Similary, rename set_serial_by_index() to release_minor() and modify it to free up the minor number of the given hso_serial. Every obtain_minor() should have corresponding release_minor() call.

Package Linux Kernel

Published 2024-02-26

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-2021-46904 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 2.6.27 and later are affected. Fixed in 4.4.268, 4.9.268, 4.14.232, 4.19.187, 5.4.112, 5.10.30, 5.11.14, 5.12 and their respective stable series.

Affected from

≥ 2.6.27

Fixed in

✓ 4.4.268 4.4.x ✓ 4.9.268 4.9.x ✓ 4.14.232 4.14.x ✓ 4.19.187 4.19.x ✓ 5.4.112 5.4.x ✓ 5.10.30 5.10.x ✓ 5.11.14 5.11.x ✓ 5.12

References

8 total

Kernel Git
https://git.kernel.org/stable/c/145c89c441d27696961752bf51b323f347601bee

Patch
Kernel Git
https://git.kernel.org/stable/c/388d05f70f1ee0cac4a2068fd295072f1a44152a

Patch
Kernel Git
https://git.kernel.org/stable/c/4a2933c88399c0ebc738db39bbce3ae89786d723

Patch
Kernel Git
https://git.kernel.org/stable/c/8a12f8836145ffe37e9c8733dce18c22fb668b66

Patch
Kernel Git
https://git.kernel.org/stable/c/92028d7a31e55d53e41cff679156b9432cffcb36

Patch

Showing 5 of 8 references View all on NVD

Details

CVE ID CVE-2021-46904

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2024-02-26

Modified 2024-11-21

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2021-46904?

CVE-2021-46904 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 2.6.27 onward and has been patched in 4.4.268, 4.9.268, 4.14.232 and others. CVE-2021-46904 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-46904?

CVE-2021-46904 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-2021-46904?

Yes. CVE-2021-46904 has been patched. Fixed versions include 4.4.268, 4.9.268, 4.14.232 and others. If you are running Linux kernel 2.6.27 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2021-46904 actively exploited?

No. CVE-2021-46904 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.