What is CVE-2021-47335?

CVE-2021-47335 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, classified as a Use After Free flaw (CWE-416), affecting Linux kernel versions from 3.8 onward and patched in 5.10.51, 5.12.18, 5.13.3 and others. CVE-2021-47335 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-47335?

CVE-2021-47335 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-2021-47335?

Yes, CVE-2021-47335 has been patched. Fixed versions include 5.10.51, 5.12.18, 5.13.3 and others. If you are running Linux kernel 3.8 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2021-47335 actively exploited?

CVE-2021-47335 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-2021-47335

Medium

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid racing on fsync_entry_slab by multi filesystem instances As syzbot reported, there is an use-after-free issue during f2fs recovery: Use-after-free write at 0xffff88823bc16040 (in kfence-#10): kmem_cache_destroy+0x1f/0x120 mm/slab_common.c:486 f2fs_recover_fsync_data+0x75b0/0x8380 fs/f2fs/recovery.c:869 f2fs_fill_super+0x9393/0xa420 fs/f2fs/super.c:3945 mount_bdev+0x26c/0x3a0 fs/super.c:1367 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x86/0x270 fs/super.c:1497 do_new_mount fs/namespace.c:2905 [inline] path_mount+0x196f/0x2be0 fs/namespace.c:3235 do_mount fs/namespace.c:3248 [inline] __do_sys_mount fs/namespace.c:3456 [inline] __se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3433 do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae The root cause is multi f2fs filesystem instances can race on accessing global fsync_entry_slab pointer, result in use-after-free issue of slab cache, fixes to init/destroy this slab cache only once during module init/destroy procedure to avoid this issue.

Package Linux Kernel

Published 2024-05-21

Last modified 2025-05-12

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-416

CVE-2021-47335 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 3.8 and later are affected. Fixed in 5.10.51, 5.12.18, 5.13.3, 5.14 and their respective stable series.

Affected from

≥ 3.8

Fixed in

✓ 5.10.51 5.10.x ✓ 5.12.18 5.12.x ✓ 5.13.3 5.13.x ✓ 5.14

References

4 total

Kernel Git
https://git.kernel.org/stable/c/79fa5d944c875711253a23b8155b36883c696409

Patch
Kernel Git
https://git.kernel.org/stable/c/86786603014e0a22d0d6af8e80ae4b8687927048

Patch
Kernel Git
https://git.kernel.org/stable/c/cad83c968c2ebe97905f900326988ed37146c347

Patch
Kernel Git
https://git.kernel.org/stable/c/e472b276a0d2180808009be38105e12754432e2a

Patch

Details

CVE ID CVE-2021-47335

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2024-05-21

Modified 2025-05-12

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2021-47335?

CVE-2021-47335 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as an Use After Free flaw (CWE-416) . It affects Linux kernel versions from 3.8 onward and has been patched in 5.10.51, 5.12.18, 5.13.3 and others. CVE-2021-47335 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-47335?

CVE-2021-47335 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-2021-47335?

Yes. CVE-2021-47335 has been patched. Fixed versions include 5.10.51, 5.12.18, 5.13.3 and others. If you are running Linux kernel 3.8 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2021-47335 actively exploited?

No. CVE-2021-47335 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.