CVE-2021-47068

High

In the Linux kernel, the following vulnerability has been resolved: net/nfc: fix use-after-free llcp_sock_bind/connect Commits 8a4cd82d ("nfc: fix refcount leak in llcp_sock_connect()") and c33b1cc62 ("nfc: fix refcount leak in llcp_sock_bind()") fixed a refcount leak bug in bind/connect but introduced a use-after-free if the same local is assigned to 2 different sockets. This can be triggered by the following simple program: int sock1 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP ); int sock2 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP ); memset( &addr, 0, sizeof(struct sockaddr_nfc_llcp) ); addr.sa_family = AF_NFC; addr.nfc_protocol = NFC_PROTO_NFC_DEP; bind( sock1, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) ) bind( sock2, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) ) close(sock1); close(sock2); Fix this by assigning NULL to llcp_sock->local after calling nfc_llcp_local_put. This addresses CVE-2021-23134.

Package Linux Kernel
Published 2024-02-29
Last modified 2025-04-22
CVSS version 3.1
Patch available
Yes

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-2021-47068 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 4.4.267, 4.9.267, 4.14.231, 4.19.187, 5.4.112, 5.10.30, 5.11.14, 5.12 and later are affected. Fixed in 4.4.269, 4.9.269, 4.14.233, 4.19.191, 5.4.119, 5.10.37, 5.11.21, 5.12.4, 5.13 and their respective stable series.

Affected from
≥ 4.4.267 ≥ 4.9.267 ≥ 4.14.231 ≥ 4.19.187 ≥ 5.4.112 ≥ 5.10.30 ≥ 5.11.14 ≥ 5.12
Fixed in
✓ 4.4.269 4.4.x ✓ 4.9.269 4.9.x ✓ 4.14.233 4.14.x ✓ 4.19.191 4.19.x ✓ 5.4.119 5.4.x ✓ 5.10.37 5.10.x ✓ 5.11.21 5.11.x ✓ 5.12.4 5.12.x ✓ 5.13

References

9 total
Showing 5 of 9 references View all on NVD

Frequently asked questions

  • What is CVE-2021-47068?

    CVE-2021-47068 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) . It affects Linux kernel versions from 4.4.267 onward and has been patched in 4.4.269, 4.9.269, 4.14.233 and others. CVE-2021-47068 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2021-47068?

    CVE-2021-47068 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-2021-47068?

    Yes. CVE-2021-47068 has been patched. Fixed versions include 4.4.269, 4.9.269, 4.14.233 and others. If you are running Linux kernel 4.4.267 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2021-47068 actively exploited?

    No. CVE-2021-47068 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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