CVE-2021-47068

HIGH
Published Feb 29, 2024 Modified Apr 22, 2025 CWE-416

Description

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.

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CVSS v3.1 Score

7.8
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Advisories & Patches

https://git.kernel.org/stable/c/18175fe17ae043a0b81e5d511f8817825784c299 https://git.kernel.org/stable/c/18ae4a192a4496e48a5490b52812645d2413307c https://git.kernel.org/stable/c/26157c82ba756767b2bd66d28a71b1bc454447f6 https://git.kernel.org/stable/c/374cdde4dcc9c909a60713abdbbf96d5e3e09f91 https://git.kernel.org/stable/c/48fba458fe54cc2a980a05c13e6c19b8b2cfb610 https://git.kernel.org/stable/c/6b7021ed36dabf29e56842e3408781cd3b82ef6e https://git.kernel.org/stable/c/c61760e6940dd4039a7f5e84a6afc9cdbf4d82b6 https://git.kernel.org/stable/c/ccddad6dd28530e716448e594c9ca7c76ccd0570 https://git.kernel.org/stable/c/e32352070bcac22be6ed8ab635debc280bb65b8c https://git.kernel.org/stable/c/18175fe17ae043a0b81e5d511f8817825784c299 https://git.kernel.org/stable/c/18ae4a192a4496e48a5490b52812645d2413307c https://git.kernel.org/stable/c/26157c82ba756767b2bd66d28a71b1bc454447f6 https://git.kernel.org/stable/c/374cdde4dcc9c909a60713abdbbf96d5e3e09f91 https://git.kernel.org/stable/c/48fba458fe54cc2a980a05c13e6c19b8b2cfb610 https://git.kernel.org/stable/c/6b7021ed36dabf29e56842e3408781cd3b82ef6e https://git.kernel.org/stable/c/c61760e6940dd4039a7f5e84a6afc9cdbf4d82b6 https://git.kernel.org/stable/c/ccddad6dd28530e716448e594c9ca7c76ccd0570 https://git.kernel.org/stable/c/e32352070bcac22be6ed8ab635debc280bb65b8c

Frequently Asked Questions

What is CVE-2021-47068? +
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. It has a CVSS v3.1 base score of 7.8 (HIGH).
How severe is CVE-2021-47068? +
CVE-2021-47068 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
What products are affected by CVE-2021-47068? +
CVE-2021-47068 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2021-47068? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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