{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47459", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-05-22T06:20:56.197Z", "datePublished": "2024-05-22T06:23:21.061Z", "dateUpdated": "2026-08-05T08:47:56.231Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:47:56.231Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv\n\nIt will trigger UAF for rx_kref of j1939_priv as following.\n\n cpu0 cpu1\nj1939_sk_bind(socket0, ndev0, ...)\nj1939_netdev_start\n j1939_sk_bind(socket1, ndev0, ...)\n j1939_netdev_start\nj1939_priv_set\n j1939_priv_get_by_ndev_locked\nj1939_jsk_add\n.....\nj1939_netdev_stop\nkref_put_lock(&priv->rx_kref, ...)\n kref_get(&priv->rx_kref, ...)\n REFCOUNT_WARN(\"addition on 0;...\")\n\n====================================================\nrefcount_t: addition on 0; use-after-free.\nWARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0\nRIP: 0010:refcount_warn_saturate+0x169/0x1e0\nCall Trace:\n j1939_netdev_start+0x68b/0x920\n j1939_sk_bind+0x426/0xeb0\n ? security_socket_bind+0x83/0xb0\n\nThe rx_kref's kref_get() and kref_put() should use j1939_netdev_lock to\nprotect." } ], "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 only through local syscalls (socket/bind/close) into j1939_sk_bind → j1939_netdev_start/stop; it is not triggered by receiving CAN/J1939 frames from the wire.\nAC:L - The race is fully attacker-controlled by opening multiple J1939 sockets and concurrently binding/closing them on the same CAN interface, as demonstrated by the syzbot threaded reproducers.\nPR:L - Creating and binding CAN_J1939 sockets requires no capabilities; an unprivileged user can reach the path on an existing UP CAN device or by creating vcan in a user/net namespace with namespaced CAP_NET_ADMIN.\nUI:N - Exploitation requires no victim action beyond the attacker’s own socket operations.\nS:U - This is a standard in-kernel memory-safety flaw affecting the host kernel authority, with no VM/IOMMU/sandbox boundary crossing.\nC:H - The vulnerability is a use-after-free on j1939_priv refcounting; UAF enables reclaim/spray of the freed object and arbitrary kernel memory disclosure.\nI:H - Use-after-free of j1939_priv state enables heap manipulation and write primitives sufficient for control-flow hijacking or arbitrary kernel writes.\nA:H - The UAF reliably produces refcount warnings and kernel oops/crash conditions even without full exploitation, denying availability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/can/j1939/main.c" ], "versions": [ { "version": "9d71dd0c70099914fcd063135da3c580865e924c", "lessThan": "a0e47d2833b4f65e6c799f28c6b636d36b8b936d", "status": "affected", "versionType": "git" }, { "version": "9d71dd0c70099914fcd063135da3c580865e924c", "lessThan": "864e77771a24c877aaf53aee019f78619cbcd668", "status": "affected", "versionType": "git" }, { "version": "9d71dd0c70099914fcd063135da3c580865e924c", "lessThan": "6e8811707e2df0c6ba920f0cad3a3bca7b42132f", "status": "affected", "versionType": "git" }, { "version": "9d71dd0c70099914fcd063135da3c580865e924c", "lessThan": "d9d52a3ebd284882f5562c88e55991add5d01586", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/can/j1939/main.c" ], "versions": [ { "version": "5.4", "status": "affected" }, { "version": "0", "lessThan": "5.4", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.156", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.76", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.14.15", "lessThanOrEqual": "5.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.4.156" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.10.76" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.14.15" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.15" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a0e47d2833b4f65e6c799f28c6b636d36b8b936d" }, { "url": "https://git.kernel.org/stable/c/864e77771a24c877aaf53aee019f78619cbcd668" }, { "url": "https://git.kernel.org/stable/c/6e8811707e2df0c6ba920f0cad3a3bca7b42132f" }, { "url": "https://git.kernel.org/stable/c/d9d52a3ebd284882f5562c88e55991add5d01586" } ], "title": "can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T05:39:59.451Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/a0e47d2833b4f65e6c799f28c6b636d36b8b936d", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/864e77771a24c877aaf53aee019f78619cbcd668", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/6e8811707e2df0c6ba920f0cad3a3bca7b42132f", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/d9d52a3ebd284882f5562c88e55991add5d01586", "tags": [ "x_transferred" ] } ] }, { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2021-47459", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-09-10T15:36:14.848678Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-09-11T17:33:25.941Z" } } ] } }