What is CVE-2021-47507?

CVE-2021-47507 is a Medium severity Linux kernel vulnerability with a CVSS score of 4.7 out of 10, classified as a Race Condition flaw (CWE-362), affecting Linux kernel versions from 5.4.102 onward and patched in 5.4.165, 5.10.85, 5.15.8 and others. CVE-2021-47507 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-47507?

CVE-2021-47507 has a CVSS score of 4.7 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2021-47507?

Yes, CVE-2021-47507 has been patched. Fixed versions include 5.4.165, 5.10.85, 5.15.8 and others. If you are running Linux kernel 5.4.102 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2021-47507 actively exploited?

CVE-2021-47507 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Race Condition (CWE-362)?

The product contains a code sequence that can run concurrently with other code, creating unexpected states. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/362.html

CVE-2021-47507

Medium

In the Linux kernel, the following vulnerability has been resolved: nfsd: Fix nsfd startup race (again) Commit bd5ae9288d64 ("nfsd: register pernet ops last, unregister first") has re-opened rpc_pipefs_event() race against nfsd_net_id registration (register_pernet_subsys()) which has been fixed by commit bb7ffbf29e76 ("nfsd: fix nsfd startup race triggering BUG_ON"). Restore the order of register_pernet_subsys() vs register_cld_notifier(). Add WARN_ON() to prevent a future regression. Crash info: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000012 CPU: 8 PID: 345 Comm: mount Not tainted 5.4.144-... #1 pc : rpc_pipefs_event+0x54/0x120 [nfsd] lr : rpc_pipefs_event+0x48/0x120 [nfsd] Call trace: rpc_pipefs_event+0x54/0x120 [nfsd] blocking_notifier_call_chain rpc_fill_super get_tree_keyed rpc_fs_get_tree vfs_get_tree do_mount ksys_mount __arm64_sys_mount el0_svc_handler el0_svc

Package Linux Kernel

Published 2024-05-24

Last modified 2025-09-24

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

4.7

out of 10

Medium

Attack Vector

Local

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Vector string

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

Weakness type

CWE-362

CVE-2021-47507 is a Race Condition vulnerability

What is Race Condition?

The product contains a code sequence that can run concurrently with other code, creating unexpected states. Learn more on MITRE CWE

Affected versions

Linux kernel versions 5.4.102, 5.10.20, 5.11.3, 5.12 and later are affected. Fixed in 5.4.165, 5.10.85, 5.15.8, 5.16 and their respective stable series.

Affected from

≥ 5.4.102 ≥ 5.10.20 ≥ 5.11.3 ≥ 5.12

Fixed in

✓ 5.4.165 5.4.x ✓ 5.10.85 5.10.x ✓ 5.15.8 5.15.x ✓ 5.16

References

4 total

Kernel Git
https://git.kernel.org/stable/c/8bf902fee5893cfc2f04a698abab47629699ae9a

Patch
Kernel Git
https://git.kernel.org/stable/c/b10252c7ae9c9d7c90552f88b544a44ee773af64

Patch
Kernel Git
https://git.kernel.org/stable/c/c520943a00ad5015704969ad3304c956bcd49d25

Patch
Kernel Git
https://git.kernel.org/stable/c/f5734b1714ca355703e9ea8fb61d04beff1790b9

Patch

Details

CVE ID CVE-2021-47507

Severity Medium

CVSS score 4.7 / 10

CVSS version 3.1

Published 2024-05-24

Modified 2025-09-24

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2021-47507?

CVE-2021-47507 is a Medium severity Linux kernel vulnerability with a CVSS score of 4.7 out of 10 , classified as a Race Condition flaw (CWE-362) . It affects Linux kernel versions from 5.4.102 onward and has been patched in 5.4.165, 5.10.85, 5.15.8 and others. CVE-2021-47507 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-47507?

CVE-2021-47507 has a CVSS score of 4.7 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2021-47507?

Yes. CVE-2021-47507 has been patched. Fixed versions include 5.4.165, 5.10.85, 5.15.8 and others. If you are running Linux kernel 5.4.102 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2021-47507 actively exploited?

No. CVE-2021-47507 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.