{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2024-46763",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2024-09-11T15:12:18.272Z",
        "datePublished": "2024-09-18T07:12:22.666Z",
        "dateUpdated": "2026-08-05T11:38:25.634Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T11:38:25.634Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfou: Fix null-ptr-deref in GRO.\n\nWe observed a null-ptr-deref in fou_gro_receive() while shutting down\na host.  [0]\n\nThe NULL pointer is sk->sk_user_data, and the offset 8 is of protocol\nin struct fou.\n\nWhen fou_release() is called due to netns dismantle or explicit tunnel\nteardown, udp_tunnel_sock_release() sets NULL to sk->sk_user_data.\nThen, the tunnel socket is destroyed after a single RCU grace period.\n\nSo, in-flight udp4_gro_receive() could find the socket and execute the\nFOU GRO handler, where sk->sk_user_data could be NULL.\n\nLet's use rcu_dereference_sk_user_data() in fou_from_sock() and add NULL\nchecks in FOU GRO handlers.\n\n[0]:\nBUG: kernel NULL pointer dereference, address: 0000000000000008\n PF: supervisor read access in kernel mode\n PF: error_code(0x0000) - not-present page\nPGD 80000001032f4067 P4D 80000001032f4067 PUD 103240067 PMD 0\nSMP PTI\nCPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.216-204.855.amzn2.x86_64 #1\nHardware name: Amazon EC2 c5.large/, BIOS 1.0 10/16/2017\nRIP: 0010:fou_gro_receive (net/ipv4/fou.c:233) [fou]\nCode: 41 5f c3 cc cc cc cc e8 e7 2e 69 f4 0f 1f 80 00 00 00 00 0f 1f 44 00 00 49 89 f8 41 54 48 89 f7 48 89 d6 49 8b 80 88 02 00 00 <0f> b6 48 08 0f b7 42 4a 66 25 fd fd 80 cc 02 66 89 42 4a 0f b6 42\nRSP: 0018:ffffa330c0003d08 EFLAGS: 00010297\nRAX: 0000000000000000 RBX: ffff93d9e3a6b900 RCX: 0000000000000010\nRDX: ffff93d9e3a6b900 RSI: ffff93d9e3a6b900 RDI: ffff93dac2e24d08\nRBP: ffff93d9e3a6b900 R08: ffff93dacbce6400 R09: 0000000000000002\nR10: 0000000000000000 R11: ffffffffb5f369b0 R12: ffff93dacbce6400\nR13: ffff93dac2e24d08 R14: 0000000000000000 R15: ffffffffb4edd1c0\nFS:  0000000000000000(0000) GS:ffff93daee800000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000000000008 CR3: 0000000102140001 CR4: 00000000007706f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nPKRU: 55555554\nCall Trace:\n <IRQ>\n ? show_trace_log_lvl (arch/x86/kernel/dumpstack.c:259)\n ? __die_body.cold (arch/x86/kernel/dumpstack.c:478 arch/x86/kernel/dumpstack.c:420)\n ? no_context (arch/x86/mm/fault.c:752)\n ? exc_page_fault (arch/x86/include/asm/irqflags.h:49 arch/x86/include/asm/irqflags.h:89 arch/x86/mm/fault.c:1435 arch/x86/mm/fault.c:1483)\n ? asm_exc_page_fault (arch/x86/include/asm/idtentry.h:571)\n ? fou_gro_receive (net/ipv4/fou.c:233) [fou]\n udp_gro_receive (include/linux/netdevice.h:2552 net/ipv4/udp_offload.c:559)\n udp4_gro_receive (net/ipv4/udp_offload.c:604)\n inet_gro_receive (net/ipv4/af_inet.c:1549 (discriminator 7))\n dev_gro_receive (net/core/dev.c:6035 (discriminator 4))\n napi_gro_receive (net/core/dev.c:6170)\n ena_clean_rx_irq (drivers/amazon/net/ena/ena_netdev.c:1558) [ena]\n ena_io_poll (drivers/amazon/net/ena/ena_netdev.c:1742) [ena]\n napi_poll (net/core/dev.c:6847)\n net_rx_action (net/core/dev.c:6917)\n __do_softirq (arch/x86/include/asm/jump_label.h:25 include/linux/jump_label.h:200 include/trace/events/irq.h:142 kernel/softirq.c:299)\n asm_call_irq_on_stack (arch/x86/entry/entry_64.S:809)\n</IRQ>\n do_softirq_own_stack (arch/x86/include/asm/irq_stack.h:27 arch/x86/include/asm/irq_stack.h:77 arch/x86/kernel/irq_64.c:77)\n irq_exit_rcu (kernel/softirq.c:393 kernel/softirq.c:423 kernel/softirq.c:435)\n common_interrupt (arch/x86/kernel/irq.c:239)\n asm_common_interrupt (arch/x86/include/asm/idtentry.h:626)\nRIP: 0010:acpi_idle_do_entry (arch/x86/include/asm/irqflags.h:49 arch/x86/include/asm/irqflags.h:89 drivers/acpi/processor_idle.c:114 drivers/acpi/processor_idle.c:575)\nCode: 8b 15 d1 3c c4 02 ed c3 cc cc cc cc 65 48 8b 04 25 40 ef 01 00 48 8b 00 a8 08 75 eb 0f 1f 44 00 00 0f 00 2d d5 09 55 00 fb f4 <fa> c3 cc cc cc cc e9 be fc ff ff 66 66 2e 0f 1f 84 00 00 00 00 00\nRSP: 0018:ffffffffb5603e58 EFLAGS: 00000246\nRAX: 0000000000004000 RBX: ffff93dac0929c00 RCX: ffff93daee833900\nRDX: ffff93daee800000 RSI: ffff93d\n---truncated---"
                }
            ],
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                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                        "baseScore": 7.5,
                        "baseSeverity": "HIGH"
                    },
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                        {
                            "lang": "en",
                            "value": "AV:N - The vulnerable code is the UDP GRO receive handler, entered from `udp4_gro_receive()` after a socket-hash lookup on any inbound UDP datagram addressed to the FOU/GUE port. Any remote host that can route a packet to that port reaches `fou_gro_receive()`/`gue_gro_receive()` directly in the NAPI path.\nAC:L - The attacker's side of the race requires only a sustained stream of ordinary UDP packets, and the NULL window is a full `synchronize_rcu()` grace period (milliseconds), so hitting it is essentially guaranteed rather than a race that must be won. FOU tunnel/netns teardown is a routine recurring event on overlay-network and container hosts, so no special preparation, reconnaissance, or target-specific conditioning is needed.\nPR:N - The GRO handler runs at packet-receive time before any FOU/GUE header validation or tunnel demultiplexing, so no credentials, handshake, or account on the target are involved. The attacker needs no privileges of any kind on the victim system.\nUI:N - No victim is tricked into any action; the crash is delivered purely by inbound packets. The tunnel teardown is an autonomous system/administrative lifecycle event, not user participation in the attack.\nS:U - The NULL dereference and the resulting panic are confined to the kernel of the affected host, with no crossing into another security authority. No hypervisor, IOMMU, or sandbox boundary is bypassed.\nC:N - The fault is a read of NULL+8 that faults immediately; no data is returned to the attacker and no kernel memory contents are disclosed. `mmap_min_addr` and SMAP prevent mapping the zero page to turn this into a controlled read.\nI:N - The bug is a read-only dereference of a NULL pointer with no write to kernel memory and no attacker-controlled value reaching any store. No control-flow hijack or data modification primitive is available.\nA:H - The dereference occurs in softirq/NAPI context, where `oops_end()` unconditionally calls `panic(\"Fatal exception in interrupt\")`, producing a full kernel panic rather than a recoverable oops. This is a complete, unrecoverable denial of service of the entire host."
                        }
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                }
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                    "programFiles": [
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                            "version": "4.7",
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                            "status": "unaffected",
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                            "status": "unaffected",
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            "title": "fou: Fix null-ptr-deref in GRO.",
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                                "timestamp": "2024-09-29T14:43:18.405859Z",
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