CVE-2025-68341

{
  "id": "CVE-2025-68341",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2025-12-23T14:16:40.683",
  "lastModified": "2026-10-19T21:10:00.160",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: reduce XDP no_direct return section to fix race\n\nAs explain in commit fa349e396e48 (\"veth: Fix race with AF_XDP exposing\nold or uninitialized descriptors\") for veth there is a chance after\nnapi_complete_done() that another CPU can manage start another NAPI\ninstance running veth_pool(). For NAPI this is correctly handled as the\nnapi_schedule_prep() check will prevent multiple instances from getting\nscheduled, but for the remaining code in veth_pool() this can run\nconcurrent with the newly started NAPI instance.\n\nThe problem/race is that xdp_clear_return_frame_no_direct() isn't\ndesigned to be nested.\n\nPrior to commit 401cb7dae813 (\"net: Reference bpf_redirect_info via\ntask_struct on PREEMPT_RT.\") the temporary BPF net context\nbpf_redirect_info was stored per CPU, where this wasn't an issue. Since\nthis commit the BPF context is stored in 'current' task_struct. When\nrunning veth in threaded-NAPI mode, then the kthread becomes the storage\narea. Now a race exists between two concurrent veth_pool() function calls\none exiting NAPI and one running new NAPI, both using the same BPF net\ncontext.\n\nRace is when another CPU gets within the xdp_set_return_frame_no_direct()\nsection before exiting veth_pool() calls the clear-function\nxdp_clear_return_frame_no_direct()."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad:\\n\\nveth: reducir la sección de retorno no_direct de XDP para corregir la condición de carrera\\n\\nComo se explica en el commit fa349e396e48 ('veth: Fix race with AF_XDP exposing old or uninitialized descriptors') para veth, existe la posibilidad de que, después de napi_complete_done(), otra CPU inicie otra instancia NAPI ejecutando veth_pool(). Para NAPI esto se maneja correctamente, ya que la verificación napi_schedule_prep() impedirá que se programen múltiples instancias, pero el código restante en veth_pool() puede ejecutarse concurrentemente con la nueva instancia NAPI iniciada.\\n\\nEl problema/condición de carrera es que xdp_clear_return_frame_no_direct() no está diseñada para ser anidada.\\n\\nVersiones anteriores al commit 401cb7dae813 ('net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.') el contexto temporal de red BPF bpf_redirect_info se almacenaba por CPU, donde esto no era un problema. Desde este commit, el contexto BPF se almacena en la estructura task_struct de 'current'. Al ejecutar veth en modo threaded?NAPI, el kthread se convierte en el área de almacenamiento. Ahora existe una condición de carrera entre dos llamadas concurrentes a la función veth_pool(): una que está saliendo de NAPI y otra que está iniciando una nueva NAPI, ambas usando el mismo contexto de red BPF.\\n\\nLa condición de carrera ocurre cuando otra CPU entra en la sección xdp_set_return_frame_no_direct() antes de que la llamada que está saliendo de veth_pool() ejecute la función de borrado xdp_clear_return_frame_no_direct()."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "drivers/net/veth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "401cb7dae8130fd34eb84648e02ab4c506df7d5e",
              "lessThan": "c1ceabcb347d1b0f7e70a7384ec7eff3847b7628",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "401cb7dae8130fd34eb84648e02ab4c506df7d5e",
              "lessThan": "d0bd018ad72a8a598ae709588934135017f8af52",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "401cb7dae8130fd34eb84648e02ab4c506df7d5e",
              "lessThan": "a14602fcae17a3f1cb8a8521bedf31728f9e7e39",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "drivers/net/veth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.11",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.11",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.61",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.17.11",
              "lessThanOrEqual": "6.17.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9
      }
    ]
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/a14602fcae17a3f1cb8a8521bedf31728f9e7e39",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c1ceabcb347d1b0f7e70a7384ec7eff3847b7628",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d0bd018ad72a8a598ae709588934135017f8af52",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}