CVE-2021-47068

net/nfc: fix use-after-free llcp_sock_bind/connect

Severity Score

7.8

*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

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.

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net/nfc: corrige use-after-free llcp_sock_bind/connect Commits 8a4cd82d ("nfc: corrige la fuga de refcount en llcp_sock_connect()") y c33b1cc62 ("nfc: corrige la fuga de refcount en llcp_sock_bind()") corrigió un error de fuga de recuento en bind/connect pero introdujo un Use-After-Free si el mismo local está asignado a 2 sockets diferentes. Esto puede activarse mediante el siguiente programa simple: int sock1 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP ); int sock2 = conector (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); cerrar(calcetín2); Solucione este problema asignando NULL a llcp_sock->local después de llamar a nfc_llcp_local_put. Esto aborda CVE-2021-23134.

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.

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Local

Attack Complexity

Low

Authentication

Single

Confidentiality

Complete

Integrity

Complete

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-02-29 CVE Reserved
2024-02-29 CVE Published
2024-12-19 CVE Updated
2025-03-19 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (17)

URL	Tag	Source
https://git.kernel.org/stable/c/a1cdd18c49d23ec38097ac2c5b0d761146fc0109	Vuln. Introduced
https://git.kernel.org/stable/c/18013007b596771bf5f5e7feee9586fb0386ad14	Vuln. Introduced
https://git.kernel.org/stable/c/538a6ff11516d38a61e237d2d2dc04c30c845fbe	Vuln. Introduced
https://git.kernel.org/stable/c/adbb1d218c5f56dbae052765da83c0f57fce2a31	Vuln. Introduced
https://git.kernel.org/stable/c/c89903c9eff219a4695e63715cf922748d743f65	Vuln. Introduced
https://git.kernel.org/stable/c/6fb003e5ae18d8cda4c8a1175d9dd8db12bec049	Vuln. Introduced
https://git.kernel.org/stable/c/8c9e4971e142e2899606a2490b77a1208c1f4638	Vuln. Introduced
https://git.kernel.org/stable/c/c33b1cc62ac05c1dbb1cdafe2eb66da01c76ca8d	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/26157c82ba756767b2bd66d28a71b1bc454447f6	2021-05-22
https://git.kernel.org/stable/c/ccddad6dd28530e716448e594c9ca7c76ccd0570	2021-05-22
https://git.kernel.org/stable/c/18ae4a192a4496e48a5490b52812645d2413307c	2021-05-22
https://git.kernel.org/stable/c/48fba458fe54cc2a980a05c13e6c19b8b2cfb610	2021-05-22
https://git.kernel.org/stable/c/e32352070bcac22be6ed8ab635debc280bb65b8c	2021-05-14
https://git.kernel.org/stable/c/6b7021ed36dabf29e56842e3408781cd3b82ef6e	2021-05-14
https://git.kernel.org/stable/c/374cdde4dcc9c909a60713abdbbf96d5e3e09f91	2021-05-14
https://git.kernel.org/stable/c/18175fe17ae043a0b81e5d511f8817825784c299	2021-05-14
https://git.kernel.org/stable/c/c61760e6940dd4039a7f5e84a6afc9cdbf4d82b6	2021-05-04

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 4.4.267 < 4.4.269 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.4.267 < 4.4.269"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 4.9.267 < 4.9.269 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.9.267 < 4.9.269"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 4.14.231 < 4.14.233 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.14.231 < 4.14.233"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 4.19.187 < 4.19.191 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.19.187 < 4.19.191"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.4.112 < 5.4.119 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.4.112 < 5.4.119"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.10.30 < 5.10.37 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.10.30 < 5.10.37"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.11.14 < 5.11.21 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.11.14 < 5.11.21"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.12 < 5.12.4 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.12 < 5.12.4"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.12 < 5.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.12 < 5.13"		en		Affected