{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47068", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-29T22:33:44.296Z", "datePublished": "2024-02-29T22:37:41.736Z", "dateUpdated": "2026-08-05T08:45:49.592Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:45:49.592Z" }, "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." } ], "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 exploit." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/nfc/llcp_sock.c" ], "versions": [ { "version": "a1cdd18c49d23ec38097ac2c5b0d761146fc0109", "lessThan": "26157c82ba756767b2bd66d28a71b1bc454447f6", "status": "affected", "versionType": "git" }, { "version": "18013007b596771bf5f5e7feee9586fb0386ad14", "lessThan": "ccddad6dd28530e716448e594c9ca7c76ccd0570", "status": "affected", "versionType": "git" }, { "version": "538a6ff11516d38a61e237d2d2dc04c30c845fbe", "lessThan": "18ae4a192a4496e48a5490b52812645d2413307c", "status": "affected", "versionType": "git" }, { "version": "adbb1d218c5f56dbae052765da83c0f57fce2a31", "lessThan": "48fba458fe54cc2a980a05c13e6c19b8b2cfb610", "status": "affected", "versionType": "git" }, { "version": "c89903c9eff219a4695e63715cf922748d743f65", "lessThan": "e32352070bcac22be6ed8ab635debc280bb65b8c", "status": "affected", "versionType": "git" }, { "version": "6fb003e5ae18d8cda4c8a1175d9dd8db12bec049", "lessThan": "6b7021ed36dabf29e56842e3408781cd3b82ef6e", "status": "affected", "versionType": "git" }, { "version": "8c9e4971e142e2899606a2490b77a1208c1f4638", "lessThan": "374cdde4dcc9c909a60713abdbbf96d5e3e09f91", "status": "affected", "versionType": "git" }, { "version": "c33b1cc62ac05c1dbb1cdafe2eb66da01c76ca8d", "lessThan": "18175fe17ae043a0b81e5d511f8817825784c299", "status": "affected", "versionType": "git" }, { "version": "c33b1cc62ac05c1dbb1cdafe2eb66da01c76ca8d", "lessThan": "c61760e6940dd4039a7f5e84a6afc9cdbf4d82b6", "status": "affected", "versionType": "git" }, { "version": "4.4.267", "lessThan": "4.4.269", "status": "affected", "versionType": "semver" }, { "version": "4.9.267", "lessThan": "4.9.269", "status": "affected", "versionType": "semver" }, { "version": "4.14.231", "lessThan": "4.14.233", "status": "affected", "versionType": "semver" }, { "version": "4.19.187", "lessThan": "4.19.191", "status": "affected", "versionType": "semver" }, { "version": "5.4.112", "lessThan": "5.4.119", "status": "affected", "versionType": "semver" }, { "version": "5.10.30", "lessThan": "5.10.37", "status": "affected", "versionType": "semver" }, { "version": "5.11.14", "lessThan": "5.11.21", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/nfc/llcp_sock.c" ], "versions": [ { "version": "5.12", "status": "affected" }, { "version": "0", "lessThan": "5.12", "status": "unaffected", "versionType": "semver" }, { "version": "4.4.269", "lessThanOrEqual": "4.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.9.269", "lessThanOrEqual": "4.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.233", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.191", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.119", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.37", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.11.21", "lessThanOrEqual": "5.11.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.12.4", "lessThanOrEqual": "5.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.13", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": 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"5.11.14", "versionEndExcluding": "5.11.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12", "versionEndExcluding": "5.12.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12", "versionEndExcluding": "5.13" } ] } ] } ], "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" } ], "title": "net/nfc: fix use-after-free llcp_sock_bind/connect", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "problemTypes": [ { "descriptions": [ { "type": "CWE", "cweId": "CWE-416", "lang": "en", "description": "CWE-416 Use After Free" } ] } ], "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "timestamp": "2025-04-22T15:46:55.659814Z", "id": "CVE-2021-47068", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": 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