What is CVE-2021-47394?

CVE-2021-47394 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, classified as a Use After Free flaw (CWE-416). CVE-2021-47394 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2021-47394?

CVE-2021-47394 has a CVSS score of 7.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2021-47394?

No patch is currently available for CVE-2021-47394. Monitor the NIST NVD and your Linux distribution's security advisories for updates.

Is CVE-2021-47394 actively exploited?

CVE-2021-47394 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-2021-47394

High

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: unlink table before deleting it syzbot reports following UAF: BUG: KASAN: use-after-free in memcmp+0x18f/0x1c0 lib/string.c:955 nla_strcmp+0xf2/0x130 lib/nlattr.c:836 nft_table_lookup.part.0+0x1a2/0x460 net/netfilter/nf_tables_api.c:570 nft_table_lookup net/netfilter/nf_tables_api.c:4064 [inline] nf_tables_getset+0x1b3/0x860 net/netfilter/nf_tables_api.c:4064 nfnetlink_rcv_msg+0x659/0x13f0 net/netfilter/nfnetlink.c:285 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504 Problem is that all get operations are lockless, so the commit_mutex held by nft_rcv_nl_event() isn't enough to stop a parallel GET request from doing read-accesses to the table object even after synchronize_rcu(). To avoid this, unlink the table first and store the table objects in on-stack scratch space.

Package Linux Kernel

Published 2024-05-21

Last modified 2025-02-03

CVSS version 3.1

Patch available

Awaiting data

CVSS 3.1 score

7.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Weakness type

CWE-416

CVE-2021-47394 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

References

The following references provide additional information about CVE-2021-47394 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/a499b03bf36b0c2e3b958a381d828678ab0ffc5e
Patch
Kernel patch commit
https://git.kernel.org/stable/c/f65c73d3aabb87d4353e0bc4a718b5ae8c43fd04
Patch

Details

CVE ID CVE-2021-47394

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2024-05-21

Modified 2025-02-03

KEV No

Patch Awaiting data

Package linux

Frequently asked questions

What is CVE-2021-47394?

CVE-2021-47394 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 , classified as an Use After Free flaw (CWE-416) . CVE-2021-47394 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2021-47394?

CVE-2021-47394 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2021-47394?

No patch is currently available for CVE-2021-47394. Monitor the NIST NVD and your Linux distribution's security advisories for updates.
Is CVE-2021-47394 actively exploited?

No — CVE-2021-47394 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (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. View CWE-416 on MITRE CWE →