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        "cveId": "CVE-2021-47232",
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        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2024-04-10T18:59:19.530Z",
        "datePublished": "2024-05-21T14:19:35.084Z",
        "dateUpdated": "2026-08-05T08:46:51.007Z"
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                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: j1939: fix Use-after-Free, hold skb ref while in use\n\nThis patch fixes a Use-after-Free found by the syzbot.\n\nThe problem is that a skb is taken from the per-session skb queue,\nwithout incrementing the ref count. This leads to a Use-after-Free if\nthe skb is taken concurrently from the session queue due to a CTS."
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                            "value": "AV:N - The UAF is reached via can_rcv → j1939_can_recv → j1939_tp_recv when processing peer TP.CM_CTS/DAT frames; an unauthenticated J1939/CAN peer drives the race, consistent with other packet-triggered j1939 scores (e.g. CVE-2024-56645).\nAC:L - The attacker controls CTS injection timing against an active TP session and can retry indefinitely; when both sides of the race are attacker-driven (local sockets/vcan or crafted bus traffic), success does not depend on conditions outside attacker influence.\nPR:N - J1939 receive processing has no authentication; a bus peer needs no credentials on the target, and the same path is also reachable from an unprivileged AF_CAN/CAN_J1939 socket with no capability checks on create/bind/send.\nUI:N - Frames are handled in softirq with no victim action required beyond a bound J1939 socket, which is the normal steady state on systems using this stack.\nS:U - The corrupted sk_buff and resulting privilege impact remain within the kernel's security authority; this is not a VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - Use-after-free of the session skb enables heap grooming and arbitrary read of freed object contents (including via continued use of the dangling skb pointer in TX/RX data paths).\nI:H - The same UAF yields a reclaimable freed sk_buff that can be sprayed for arbitrary write and control-flow hijacking primitives in the kernel heap.\nA:H - Dereferencing the freed skb causes kernel oops/panic, and an unauthenticated peer can trigger the race repeatedly to deny service."
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