FKIE_CVE-2026-74615

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-10-14 13:10
Severity
8.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: vxlan: do not arm the ageing timer on a device that is down vxlan_changelink() arms vxlan->age_timer whenever the requested ageing interval differs from the configured one: if (conf.age_interval != vxlan->cfg.age_interval) mod_timer(&vxlan->age_timer, jiffies); There is no netif_running() test, so the timer is armed even on a device that was never brought up. The only synchronous cancel in the driver is the timer_delete_sync() in vxlan_stop(), which is .ndo_stop. netif_close_many() drops devices without IFF_UP before __dev_close_many() runs, so that cancel is skipped for such a device. vxlan_setup() sets dev->needs_free_netdev = true and age_timer is a member of struct vxlan_dev, so free_netdev() releases the allocation the timer lives in while it is still queued on a timer_base. expire_timers() unlinks the entry before it loads timer->function, so the timer core writes through the freed object's list pointers: BUG: KASAN: slab-use-after-free in __run_timers+0x208/0x654 Write of size 8 at addr ffff00001adace68 by task true/192 __asan_store8+0x84/0xac __run_timers+0x208/0x654 run_timer_softirq+0x154/0x18c Allocated by task 189: alloc_netdev_mqs+0x64/0x720 rtnl_create_link+0x4ac/0x520 rtnl_newlink+0x758/0xd00 Freed by task 191: netdev_release+0x40/0x58 netdev_run_todo+0x4a4/0x8c0 rtnl_dellink+0x200/0x4e8 The rtnl operations involved are netns-scoped, so an unprivileged user can perform them in a new user and network namespace. Arming the timer on a down device never had an effect: vxlan_cleanup() returns early on !netif_running(), and vxlan_open() arms the timer for any non-zero interval once the device is brought up. Add the missing test. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/26c179d47403d2f919ee914cc02c31d896b59fee
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/46bb297ad77680e009244f067f27d51cf5b8c7cf
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/619dd29045e439d0b0f8c6d4fec1af447a050680
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b095e99b9e67ea31f0c4b00260e010898253519
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b4119af544996a545cf84b16f1dbce829ba0de8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9dc561f0522c35bdd66e0646a748814a138ec4ca
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b37971686ec59fb027fa4910ba16805e68fddb97
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/be44d79d14d7f9ae7c8ffb7272142005341b5123
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/vxlan/vxlan_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "be44d79d14d7f9ae7c8ffb7272142005341b5123",
              "status": "affected",
              "version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
              "versionType": "git"
            },
            {
              "lessThan": "26c179d47403d2f919ee914cc02c31d896b59fee",
              "status": "affected",
              "version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
              "versionType": "git"
            },
            {
              "lessThan": "9dc561f0522c35bdd66e0646a748814a138ec4ca",
              "status": "affected",
              "version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
              "versionType": "git"
            },
            {
              "lessThan": "619dd29045e439d0b0f8c6d4fec1af447a050680",
              "status": "affected",
              "version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
              "versionType": "git"
            },
            {
              "lessThan": "6b095e99b9e67ea31f0c4b00260e010898253519",
              "status": "affected",
              "version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
              "versionType": "git"
            },
            {
              "lessThan": "46bb297ad77680e009244f067f27d51cf5b8c7cf",
              "status": "affected",
              "version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
              "versionType": "git"
            },
            {
              "lessThan": "6b4119af544996a545cf84b16f1dbce829ba0de8",
              "status": "affected",
              "version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
              "versionType": "git"
            },
            {
              "lessThan": "b37971686ec59fb027fa4910ba16805e68fddb97",
              "status": "affected",
              "version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/vxlan/vxlan_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.0"
            },
            {
              "lessThan": "5.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.152",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: do not arm the ageing timer on a device that is down\n\nvxlan_changelink() arms vxlan-\u003eage_timer whenever the requested ageing\ninterval differs from the configured one:\n\n\tif (conf.age_interval != vxlan-\u003ecfg.age_interval)\n\t\tmod_timer(\u0026vxlan-\u003eage_timer, jiffies);\n\nThere is no netif_running() test, so the timer is armed even on a device\nthat was never brought up.  The only synchronous cancel in the driver is\nthe timer_delete_sync() in vxlan_stop(), which is .ndo_stop.\nnetif_close_many() drops devices without IFF_UP before\n__dev_close_many() runs, so that cancel is skipped for such a device.\n\nvxlan_setup() sets dev-\u003eneeds_free_netdev = true and age_timer is a\nmember of struct vxlan_dev, so free_netdev() releases the allocation the\ntimer lives in while it is still queued on a timer_base.\nexpire_timers() unlinks the entry before it loads timer-\u003efunction, so\nthe timer core writes through the freed object\u0027s list pointers:\n\n  BUG: KASAN: slab-use-after-free in __run_timers+0x208/0x654\n  Write of size 8 at addr ffff00001adace68 by task true/192\n   __asan_store8+0x84/0xac\n   __run_timers+0x208/0x654\n   run_timer_softirq+0x154/0x18c\n  Allocated by task 189:\n   alloc_netdev_mqs+0x64/0x720\n   rtnl_create_link+0x4ac/0x520\n   rtnl_newlink+0x758/0xd00\n  Freed by task 191:\n   netdev_release+0x40/0x58\n   netdev_run_todo+0x4a4/0x8c0\n   rtnl_dellink+0x200/0x4e8\n\nThe rtnl operations involved are netns-scoped, so an unprivileged user\ncan perform them in a new user and network namespace.\n\nArming the timer on a down device never had an effect: vxlan_cleanup()\nreturns early on !netif_running(), and vxlan_open() arms the timer for\nany non-zero interval once the device is brought up.  Add the missing\ntest.\n\nDiscovered by XBOW, triaged by Baul Lee \u003cbaul.lee@xbow.com\u003e"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nvxlan: no activar el temporizador de envejecimiento en un dispositivo que est\u00e1 inactivo\n\nvxlan_changelink() activa vxlan -\u003e age_timer siempre que el intervalo de envejecimiento solicitado difiera del configurado:\n\n\tif (conf.age_interval != vxlan -\u003e cfg.age_interval)\n\t\tmod_timer(\u0026vxlan -\u003e age_timer, jiffies);\n\nNo hay una prueba netif_running(), por lo que el temporizador se activa incluso en un dispositivo que nunca se inici\u00f3. La \u00fanica cancelaci\u00f3n s\u00edncrona en el controlador es timer_delete_sync() en vxlan_stop(), que es .ndo_stop. netif_close_many() descarta dispositivos sin IFF_UP antes de que se ejecute __dev_close_many(), por lo que esa cancelaci\u00f3n se omite para dicho dispositivo.\n\nvxlan_setup() establece dev -\u003e needs_free_netdev = true y age_timer es un miembro de struct vxlan_dev, por lo que free_netdev() libera la asignaci\u00f3n en la que reside el temporizador mientras a\u00fan est\u00e1 en cola en una timer_base. expire_timers() desvincula la entrada antes de que cargue timer -\u003e function, por lo que el n\u00facleo del temporizador escribe a trav\u00e9s de los punteros de lista del objeto liberado:\n\n  ERROR: KASAN: uso despu\u00e9s de liberaci\u00f3n de slab en __run_timers+0x208/0x654\n  Escritura de tama\u00f1o 8 en la direcci\u00f3n ffff00001adace68 por la tarea true/192\n   __asan_store8+0x84/0xac\n   __run_timers+0x208/0x654\n   run_timer_softirq+0x154/0x18c\n  Asignado por la tarea 189:\n   alloc_netdev_mqs+0x64/0x720\n   rtnl_create_link+0x4ac/0x520\n   rtnl_newlink+0x758/0xd00\n  Liberado por la tarea 191:\n   netdev_release+0x40/0x58\n   netdev_run_todo+0x4a4/0x8c0\n   rtnl_dellink+0x200/0x4e8\n\nLas operaciones rtnl involucradas tienen alcance netns, por lo que un usuario sin privilegios puede realizarlas en un nuevo espacio de nombres de usuario y de red.\n\nActivar el temporizador en un dispositivo inactivo nunca tuvo efecto: vxlan_cleanup() retorna anticipadamente en !netif_running(), y vxlan_open() activa el temporizador para cualquier intervalo distinto de cero una vez que el dispositivo se inicia. A\u00f1adir la prueba que falta.\n\nDescubierto por XBOW, clasificado por Baul Lee \u003cbaul.lee@xbow.com\u003e"
    }
  ],
  "id": "CVE-2026-74615",
  "lastModified": "2026-10-14T13:10:00.187",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 6.0,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:34.143",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/26c179d47403d2f919ee914cc02c31d896b59fee"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/46bb297ad77680e009244f067f27d51cf5b8c7cf"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/619dd29045e439d0b0f8c6d4fec1af447a050680"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6b095e99b9e67ea31f0c4b00260e010898253519"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6b4119af544996a545cf84b16f1dbce829ba0de8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9dc561f0522c35bdd66e0646a748814a138ec4ca"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b37971686ec59fb027fa4910ba16805e68fddb97"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/be44d79d14d7f9ae7c8ffb7272142005341b5123"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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