{"id":"CVE-2021-47068","state":"PUBLISHED","title":"net/nfc: fix use-after-free llcp_sock_bind/connect","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/nfc: fix use-after-free llcp_sock_bind/connect\n\nCommits 8a4cd82d (\"nfc: fix refcount leak in llcp_sock_connect()\")\nand c33b1cc62 (\"nfc: fix refcount leak in llcp_sock_bind()\")\nfixed a refcount leak bug in bind/connect but introduced a\nuse-after-free if the same local is assigned to 2 different sockets.\n\nThis can be triggered by the following simple program:\n    int sock1 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP );\n    int sock2 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP );\n    memset( &addr, 0, sizeof(struct sockaddr_nfc_llcp) );\n    addr.sa_family = AF_NFC;\n    addr.nfc_protocol = NFC_PROTO_NFC_DEP;\n    bind( sock1, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) )\n    bind( sock2, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) )\n    close(sock1);\n    close(sock2);\n\nFix this by assigning NULL to llcp_sock->local after calling\nnfc_llcp_local_put.\n\nThis addresses CVE-2021-23134.","publishedAt":"2024-02-29T22:37:41.736Z","updatedAt":"2026-08-05T08:45:49.592Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a1cdd18c49d23ec38097ac2c5b0d761146fc0109","status":"affected","lessThan":"26157c82ba756767b2bd66d28a71b1bc454447f6","versionType":"git"},{"version":"18013007b596771bf5f5e7feee9586fb0386ad14","status":"affected","lessThan":"ccddad6dd28530e716448e594c9ca7c76ccd0570","versionType":"git"},{"version":"538a6ff11516d38a61e237d2d2dc04c30c845fbe","status":"affected","lessThan":"18ae4a192a4496e48a5490b52812645d2413307c","versionType":"git"},{"version":"adbb1d218c5f56dbae052765da83c0f57fce2a31","status":"affected","lessThan":"48fba458fe54cc2a980a05c13e6c19b8b2cfb610","versionType":"git"},{"version":"c89903c9eff219a4695e63715cf922748d743f65","status":"affected","lessThan":"e32352070bcac22be6ed8ab635debc280bb65b8c","versionType":"git"},{"version":"6fb003e5ae18d8cda4c8a1175d9dd8db12bec049","status":"affected","lessThan":"6b7021ed36dabf29e56842e3408781cd3b82ef6e","versionType":"git"},{"version":"8c9e4971e142e2899606a2490b77a1208c1f4638","status":"affected","lessThan":"374cdde4dcc9c909a60713abdbbf96d5e3e09f91","versionType":"git"},{"version":"c33b1cc62ac05c1dbb1cdafe2eb66da01c76ca8d","status":"affected","lessThan":"18175fe17ae043a0b81e5d511f8817825784c299","versionType":"git"},{"version":"c33b1cc62ac05c1dbb1cdafe2eb66da01c76ca8d","status":"affected","lessThan":"c61760e6940dd4039a7f5e84a6afc9cdbf4d82b6","versionType":"git"},{"version":"4.4.267","status":"affected","lessThan":"4.4.269","versionType":"semver"},{"version":"4.9.267","status":"affected","lessThan":"4.9.269","versionType":"semver"},{"version":"4.14.231","status":"affected","lessThan":"4.14.233","versionType":"semver"},{"version":"4.19.187","status":"affected","lessThan":"4.19.191","versionType":"semver"},{"version":"5.4.112","status":"affected","lessThan":"5.4.119","versionType":"semver"},{"version":"5.10.30","status":"affected","lessThan":"5.10.37","versionType":"semver"},{"version":"5.11.14","status":"affected","lessThan":"5.11.21","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/nfc/llcp_sock.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.12","versionType":"semver"},{"version":"4.4.269","status":"unaffected","lessThanOrEqual":"4.4.*","versionType":"semver"},{"version":"4.9.269","status":"unaffected","lessThanOrEqual":"4.9.*","versionType":"semver"},{"version":"4.14.233","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.191","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.119","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.37","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.11.21","status":"unaffected","lessThanOrEqual":"5.11.*","versionType":"semver"},{"version":"5.12.4","status":"unaffected","lessThanOrEqual":"5.12.*","versionType":"semver"},{"version":"5.13","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/nfc/llcp_sock.c"]}],"references":["https://git.kernel.org/stable/c/26157c82ba756767b2bd66d28a71b1bc454447f6","https://git.kernel.org/stable/c/ccddad6dd28530e716448e594c9ca7c76ccd0570","https://git.kernel.org/stable/c/18ae4a192a4496e48a5490b52812645d2413307c","https://git.kernel.org/stable/c/48fba458fe54cc2a980a05c13e6c19b8b2cfb610","https://git.kernel.org/stable/c/e32352070bcac22be6ed8ab635debc280bb65b8c","https://git.kernel.org/stable/c/6b7021ed36dabf29e56842e3408781cd3b82ef6e","https://git.kernel.org/stable/c/374cdde4dcc9c909a60713abdbbf96d5e3e09f91","https://git.kernel.org/stable/c/18175fe17ae043a0b81e5d511f8817825784c299","https://git.kernel.org/stable/c/c61760e6940dd4039a7f5e84a6afc9cdbf4d82b6"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T19:49:19.404Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/47xxx/CVE-2021-47068.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47068","state":"PUBLISHED","datePublished":"2024-02-29T22:37:41.736Z","dateUpdated":"2026-08-05T08:45:49.592Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-02-29T22:33:44.296Z"},"containers":{"cna":{"title":"net/nfc: fix use-after-free llcp_sock_bind/connect","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/nfc: fix use-after-free llcp_sock_bind/connect\n\nCommits 8a4cd82d (\"nfc: fix refcount leak in llcp_sock_connect()\")\nand c33b1cc62 (\"nfc: fix refcount leak in llcp_sock_bind()\")\nfixed a refcount leak bug in bind/connect but introduced a\nuse-after-free if the same local is assigned to 2 different sockets.\n\nThis can be triggered by the following simple program:\n    int sock1 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP );\n    int sock2 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP );\n    memset( &addr, 0, sizeof(struct sockaddr_nfc_llcp) );\n    addr.sa_family = AF_NFC;\n    addr.nfc_protocol = NFC_PROTO_NFC_DEP;\n    bind( sock1, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) )\n    bind( sock2, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) )\n    close(sock1);\n    close(sock2);\n\nFix this by assigning NULL to llcp_sock->local after calling\nnfc_llcp_local_put.\n\nThis addresses CVE-2021-23134."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a1cdd18c49d23ec38097ac2c5b0d761146fc0109","status":"affected","lessThan":"26157c82ba756767b2bd66d28a71b1bc454447f6","versionType":"git"},{"version":"18013007b596771bf5f5e7feee9586fb0386ad14","status":"affected","lessThan":"ccddad6dd28530e716448e594c9ca7c76ccd0570","versionType":"git"},{"version":"538a6ff11516d38a61e237d2d2dc04c30c845fbe","status":"affected","lessThan":"18ae4a192a4496e48a5490b52812645d2413307c","versionType":"git"},{"version":"adbb1d218c5f56dbae052765da83c0f57fce2a31","status":"affected","lessThan":"48fba458fe54cc2a980a05c13e6c19b8b2cfb610","versionType":"git"},{"version":"c89903c9eff219a4695e63715cf922748d743f65","status":"affected","lessThan":"e32352070bcac22be6ed8ab635debc280bb65b8c","versionType":"git"},{"version":"6fb003e5ae18d8cda4c8a1175d9dd8db12bec049","status":"affected","lessThan":"6b7021ed36dabf29e56842e3408781cd3b82ef6e","versionType":"git"},{"version":"8c9e4971e142e2899606a2490b77a1208c1f4638","status":"affected","lessThan":"374cdde4dcc9c909a60713abdbbf96d5e3e09f91","versionType":"git"},{"version":"c33b1cc62ac05c1dbb1cdafe2eb66da01c76ca8d","status":"affected","lessThan":"18175fe17ae043a0b81e5d511f8817825784c299","versionType":"git"},{"version":"c33b1cc62ac05c1dbb1cdafe2eb66da01c76ca8d","status":"affected","lessThan":"c61760e6940dd4039a7f5e84a6afc9cdbf4d82b6","versionType":"git"},{"version":"4.4.267","status":"affected","lessThan":"4.4.269","versionType":"semver"},{"version":"4.9.267","status":"affected","lessThan":"4.9.269","versionType":"semver"},{"version":"4.14.231","status":"affected","lessThan":"4.14.233","versionType":"semver"},{"version":"4.19.187","status":"affected","lessThan":"4.19.191","versionType":"semver"},{"version":"5.4.112","status":"affected","lessThan":"5.4.119","versionType":"semver"},{"version":"5.10.30","status":"affected","lessThan":"5.10.37","versionType":"semver"},{"version":"5.11.14","status":"affected","lessThan":"5.11.21","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/nfc/llcp_sock.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.12","versionType":"semver"},{"version":"4.4.269","status":"unaffected","lessThanOrEqual":"4.4.*","versionType":"semver"},{"version":"4.9.269","status":"unaffected","lessThanOrEqual":"4.9.*","versionType":"semver"},{"version":"4.14.233","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.191","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.119","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.37","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.11.21","status":"unaffected","lessThanOrEqual":"5.11.*","versionType":"semver"},{"version":"5.12.4","status":"unaffected","lessThanOrEqual":"5.12.*","versionType":"semver"},{"version":"5.13","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/nfc/llcp_sock.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/26157c82ba756767b2bd66d28a71b1bc454447f6"},{"url":"https://git.kernel.org/stable/c/ccddad6dd28530e716448e594c9ca7c76ccd0570"},{"url":"https://git.kernel.org/stable/c/18ae4a192a4496e48a5490b52812645d2413307c"},{"url":"https://git.kernel.org/stable/c/48fba458fe54cc2a980a05c13e6c19b8b2cfb610"},{"url":"https://git.kernel.org/stable/c/e32352070bcac22be6ed8ab635debc280bb65b8c"},{"url":"https://git.kernel.org/stable/c/6b7021ed36dabf29e56842e3408781cd3b82ef6e"},{"url":"https://git.kernel.org/stable/c/374cdde4dcc9c909a60713abdbbf96d5e3e09f91"},{"url":"https://git.kernel.org/stable/c/18175fe17ae043a0b81e5d511f8817825784c299"},{"url":"https://git.kernel.org/stable/c/c61760e6940dd4039a7f5e84a6afc9cdbf4d82b6"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached via local AF_NFC SOCK_STREAM socket/bind/close syscalls on the LLCP path, not by processing NFC frames from a peer; an NFC device must exist but the trigger itself is local userspace.\nAC:L - The PoC is deterministic with no race: two binds that fail after assigning the shared local, then close, reliably free and re-use the object under full attacker control of both sockets and timing for heap spray.\nPR:L - SOCK_STREAM/DGRAM LLCP sockets require no capabilities (only SOCK_RAW checks CAP_NET_RAW); an unprivileged local user can trigger this on a system with an NFC device (e.g., Android/phone), matching the researchers' unprivileged LPE claim.\nUI:N - The attacker runs their own program to create sockets, bind, and close; no victim interaction is required.\nS:U - This is a standard in-kernel UAF privilege escalation within the host kernel's security authority, not a VM/IOMMU/sandbox boundary crossing.\nC:H - Use-after-free of the heap-allocated nfc_llcp_local object enables reclaim and arbitrary read primitives, supporting full confidentiality impact and privilege escalation.\nI:H - The same UAF provides a write primitive via controlled reclaim of the freed local object, enabling corruption/control-flow hijacking and privilege escalation as reported.\nA:H - The UAF causes refcount underflow, kernel warnings/oops, and crash on misuse of the freed local, so availability impact is high even without a full 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