Vulnerability Details 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 1.1%
CVSS Severity
CVSS v3 Score 7.8
Products affected by CVE-2021-47068
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cpe:2.3:o:linux:linux_kernel:4.14.231
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cpe:2.3:o:linux:linux_kernel:4.14.232
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cpe:2.3:o:linux:linux_kernel:4.19.187
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cpe:2.3:o:linux:linux_kernel:4.19.188
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cpe:2.3:o:linux:linux_kernel:4.19.189
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cpe:2.3:o:linux:linux_kernel:4.19.190
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cpe:2.3:o:linux:linux_kernel:4.4.267
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cpe:2.3:o:linux:linux_kernel:4.4.268
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cpe:2.3:o:linux:linux_kernel:4.9.267
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cpe:2.3:o:linux:linux_kernel:4.9.268
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cpe:2.3:o:linux:linux_kernel:5.10.30
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cpe:2.3:o:linux:linux_kernel:5.10.31
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cpe:2.3:o:linux:linux_kernel:5.10.32
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cpe:2.3:o:linux:linux_kernel:5.10.33
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cpe:2.3:o:linux:linux_kernel:5.10.34
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cpe:2.3:o:linux:linux_kernel:5.10.35
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cpe:2.3:o:linux:linux_kernel:5.10.36
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cpe:2.3:o:linux:linux_kernel:5.11.14
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cpe:2.3:o:linux:linux_kernel:5.11.15
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cpe:2.3:o:linux:linux_kernel:5.11.16
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cpe:2.3:o:linux:linux_kernel:5.11.17
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cpe:2.3:o:linux:linux_kernel:5.11.18
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cpe:2.3:o:linux:linux_kernel:5.11.19
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cpe:2.3:o:linux:linux_kernel:5.11.20
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cpe:2.3:o:linux:linux_kernel:5.12
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cpe:2.3:o:linux:linux_kernel:5.12.1
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cpe:2.3:o:linux:linux_kernel:5.12.2
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cpe:2.3:o:linux:linux_kernel:5.12.3
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cpe:2.3:o:linux:linux_kernel:5.4.112
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cpe:2.3:o:linux:linux_kernel:5.4.113
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cpe:2.3:o:linux:linux_kernel:5.4.114
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cpe:2.3:o:linux:linux_kernel:5.4.115
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cpe:2.3:o:linux:linux_kernel:5.4.116
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cpe:2.3:o:linux:linux_kernel:5.4.117
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cpe:2.3:o:linux:linux_kernel:5.4.118