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CVE-2025-38440

Estado: ModificadaMedia (4.7)—

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5e: Fix race between DIM disable and net_dim()

There's a race between disabling DIM and NAPI callbacks using the dim pointer on the RQ or SQ.

If NAPI checks the DIM state bit and sees it still set, it assumes `rq->dim` or `sq->dim` is valid. But if DIM gets disabled right after that check, the pointer might already be set to NULL, leading to a NULL pointer dereference in net_dim().

Fix this by calling `synchronize_net()` before freeing the DIM context. This ensures all in-progress NAPI callbacks are finished before the pointer is cleared.

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Kernel log:

Detalles técnicos trazas, registros y código del informe original
BUG: kernel NULL pointer dereference, address: 0000000000000000
...
RIP: 0010:net_dim+0x23/0x190
...
Call Trace:
 <TASK>
 ? __die+0x20/0x60
 ? page_fault_oops+0x150/0x3e0
 ? common_interrupt+0xf/0xa0
 ? sysvec_call_function_single+0xb/0x90
 ? exc_page_fault+0x74/0x130
 ? asm_exc_page_fault+0x22/0x30
 ? net_dim+0x23/0x190
 ? mlx5e_poll_ico_cq+0x41/0x6f0 [mlx5_core]
 ? sysvec_apic_timer_interrupt+0xb/0x90
 mlx5e_handle_rx_dim+0x92/0xd0 [mlx5_core]
 mlx5e_napi_poll+0x2cd/0xac0 [mlx5_core]
 ? mlx5e_poll_ico_cq+0xe5/0x6f0 [mlx5_core]
 busy_poll_stop+0xa2/0x200
 ? mlx5e_napi_poll+0x1d9/0xac0 [mlx5_core]
 ? mlx5e_trigger_irq+0x130/0x130 [mlx5_core]
 __napi_busy_loop+0x345/0x3b0
 ? sysvec_call_function_single+0xb/0x90
 ? asm_sysvec_call_function_single+0x16/0x20
 ? sysvec_apic_timer_interrupt+0xb/0x90
 ? pcpu_free_area+0x1e4/0x2e0
 napi_busy_loop+0x11/0x20
 xsk_recvmsg+0x10c/0x130
 sock_recvmsg+0x44/0x70
 __sys_recvfrom+0xbc/0x130
 ? __schedule+0x398/0x890
 __x64_sys_recvfrom+0x20/0x30
 do_syscall_64+0x4c/0x100
 entry_SYSCALL_64_after_hwframe+0x4b/0x53
...
---[ end trace 0000000000000000 ]---
...
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2025-38440",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "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"
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        "impactScore": 5.9,
        "exploitabilityScore": 1.8
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          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
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        "exploitabilityScore": 1
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          "product": "Linux",
          "versions": [
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          "programFiles": [
            "drivers/net/ethernet/mellanox/mlx5/core/en_dim.c"
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          "value": "CWE-362"
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      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Fix race between DIM disable and net_dim()\n\nThere's a race between disabling DIM and NAPI callbacks using the dim\npointer on the RQ or SQ.\n\nIf NAPI checks the DIM state bit and sees it still set, it assumes\n`rq->dim` or `sq->dim` is valid. But if DIM gets disabled right after\nthat check, the pointer might already be set to NULL, leading to a NULL\npointer dereference in net_dim().\n\nFix this by calling `synchronize_net()` before freeing the DIM context.\nThis ensures all in-progress NAPI callbacks are finished before the\npointer is cleared.\n\nKernel log:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000000\n...\nRIP: 0010:net_dim+0x23/0x190\n...\nCall Trace:\n <TASK>\n ? __die+0x20/0x60\n ? page_fault_oops+0x150/0x3e0\n ? common_interrupt+0xf/0xa0\n ? sysvec_call_function_single+0xb/0x90\n ? exc_page_fault+0x74/0x130\n ? asm_exc_page_fault+0x22/0x30\n ? net_dim+0x23/0x190\n ? mlx5e_poll_ico_cq+0x41/0x6f0 [mlx5_core]\n ? sysvec_apic_timer_interrupt+0xb/0x90\n mlx5e_handle_rx_dim+0x92/0xd0 [mlx5_core]\n mlx5e_napi_poll+0x2cd/0xac0 [mlx5_core]\n ? mlx5e_poll_ico_cq+0xe5/0x6f0 [mlx5_core]\n busy_poll_stop+0xa2/0x200\n ? mlx5e_napi_poll+0x1d9/0xac0 [mlx5_core]\n ? mlx5e_trigger_irq+0x130/0x130 [mlx5_core]\n __napi_busy_loop+0x345/0x3b0\n ? sysvec_call_function_single+0xb/0x90\n ? asm_sysvec_call_function_single+0x16/0x20\n ? sysvec_apic_timer_interrupt+0xb/0x90\n ? pcpu_free_area+0x1e4/0x2e0\n napi_busy_loop+0x11/0x20\n xsk_recvmsg+0x10c/0x130\n sock_recvmsg+0x44/0x70\n __sys_recvfrom+0xbc/0x130\n ? __schedule+0x398/0x890\n __x64_sys_recvfrom+0x20/0x30\n do_syscall_64+0x4c/0x100\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n...\n---[ end trace 0000000000000000 ]---\n...\n---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net/mlx5e: Se corrige la competencia entre la desactivación de DIM y net_dim(). Existe una competencia entre la desactivación de las devoluciones de llamada de DIM y NAPI mediante el puntero dim en el RQ o SQ. Si NAPI comprueba el bit de estado de DIM y lo ve aún establecido, asume que `rq-&gt;dim` o `sq-&gt;dim` son válidos. Sin embargo, si DIM se desactiva justo después de dicha comprobación, es posible que el puntero ya esté establecido en NULL, lo que provoca una desreferencia de puntero NULL en net_dim(). Para solucionar esto, llame a `synchronize_net()` antes de liberar el contexto de DIM. Esto garantiza que todas las devoluciones de llamada de NAPI en curso finalicen antes de que se borre el puntero. Kernel log: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... RIP: 0010:net_dim+0x23/0x190 ... Call Trace:  ? __die+0x20/0x60 ? page_fault_oops+0x150/0x3e0 ? common_interrupt+0xf/0xa0 ? sysvec_call_function_single+0xb/0x90 ? exc_page_fault+0x74/0x130 ? asm_exc_page_fault+0x22/0x30 ? net_dim+0x23/0x190 ? mlx5e_poll_ico_cq+0x41/0x6f0 [mlx5_core] ? sysvec_apic_timer_interrupt+0xb/0x90 mlx5e_handle_rx_dim+0x92/0xd0 [mlx5_core] mlx5e_napi_poll+0x2cd/0xac0 [mlx5_core] ? mlx5e_poll_ico_cq+0xe5/0x6f0 [mlx5_core] busy_poll_stop+0xa2/0x200 ? mlx5e_napi_poll+0x1d9/0xac0 [mlx5_core] ? mlx5e_trigger_irq+0x130/0x130 [mlx5_core] __napi_busy_loop+0x345/0x3b0 ? sysvec_call_function_single+0xb/0x90 ? asm_sysvec_call_function_single+0x16/0x20 ? sysvec_apic_timer_interrupt+0xb/0x90 ? pcpu_free_area+0x1e4/0x2e0 napi_busy_loop+0x11/0x20 xsk_recvmsg+0x10c/0x130 sock_recvmsg+0x44/0x70 __sys_recvfrom+0xbc/0x130 ? __schedule+0x398/0x890 __x64_sys_recvfrom+0x20/0x30 do_syscall_64+0x4c/0x100 entry_SYSCALL_64_after_hwframe+0x4b/0x53 ... ---[ end trace 0000000000000000 ]--- ... ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---"
    }
  ],
  "lastModified": "2026-07-30T06:23:14.567",
  "configurations": [
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      "nodes": [
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