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CVE-2026-90071

Estado: RecibidaAlta (7.8)—

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

net/sched: sch_teql: restore skb->dev on the slave failure path

teql_master_xmit() sets skb->dev = slave before calling the slave's ndo_start_xmit(), but never restores it when that transmit fails. The skb then walks on to the next slave still pointing at the previous one.

If a later slave has no resolved neighbour, teql_resolve() hands the skb to neigh_event_send(), which queues it on that neighbour's arp_queue with the stale skb->dev. skb->dev holds no reference, so deleting the previous slave frees the net_device while the skb is still queued.

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Whatever runs next on that skb - arp_error_report() on timeout, or neigh_direct_output() -> dev_queue_xmit() once the neighbour resolves - causes a UAF like the one below:

BUG: KASAN: slab-use-after-free in __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) Read of size 4 at addr ffff888106e100b0 by task flood_packet/527 CPU: 0 UID: 0 PID: 527 Comm: flood_packet Not tainted 7.2.0-rc6-g594d90519502 #1 PREEMPT(lazy) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <IRQ> dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) ? __pfx__raw_spin_lock_irqsave (./include/asm-generic/qrwlock.h:122 (discriminator 4)) ? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) kasan_report (mm/kasan/report.c:595) ? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) [...] ipv4_link_failure (net/ipv4/route.c:1251 net/ipv4/route.c:1258) ? __pfx_ipv4_link_failure (./include/linux/skbuff.h:4327) ? _raw_write_lock (./include/linux/instrumented.h:55 ./include/linux/atomic/atomic-instrumented.h:1301 ./include/asm-generic/qrwlock.h:98 ./include/linux/rwlock_api_smp.h:230 kernel/locking/spinlock.c:304) ? __pfx__raw_write_lock (kernel/locking/spinlock.c:175) arp_error_report (./include/net/dst.h:438 net/ipv4/arp.c:296) neigh_invalidate (net/core/neighbour.c:1077) neigh_timer_handler (net/core/neighbour.c:1169) [...] Allocated by task 505: kasan_save_stack (mm/kasan/common.c:57) kasan_save_track (mm/kasan/common.c:78) __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415) __kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5334 mm/slub.c:6905) alloc_netdev_mqs (net/core/dev.c:12055 (discriminator 2)) rtnl_create_link (net/core/rtnetlink.c:3721) rtnl_newlink (net/core/rtnetlink.c:3903 net/core/rtnetlink.c:4044 net/core/rtnetlink.c:4159) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) [...] Freed by task 536: kasan_save_stack (mm/kasan/common.c:57) kasan_save_track (mm/kasan/common.c:78) kasan_save_free_info (mm/kasan/generic.c:584) __kasan_slab_free (mm/kasan/common.c:253 mm/kasan/common.c:285) kfree (./include/linux/kasan.h:235 mm/slub.c:2677 mm/slub.c:6377 mm/slub.c:6692) device_release (drivers/base/core.c:2636) kobject_put (lib/kobject.c:689 lib/kobject.c:720 ./include/linux/kref.h:65 lib/kobject.c:737) netdev_run_todo (net/core/dev.c:11756) rtnl_dellink (net/core/rtnetlink.c:157 ./include/linux/rtnetlink.h:135 net/core/rtnetlink.c:3651) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) [...]

Fix this by restoring skb->dev to the master at the end of each slave's iteration.

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad de uso después de liberación (UAF) en kernel Linux que requiere acceso local (AV:L, PR:L) para disparar condición de carrera. Permite negación de servicio mediante crash o corrupción de memoria en el subsistema de red (teql).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-90071",
  "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"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
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          "vendor": "Linux",
          "product": "Linux",
          "versions": [
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              "lessThan": "6.20",
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          ],
          "programFiles": [
            "net/sched/sch_teql.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
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              "version": "7.0"
            },
            {
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              "version": "0",
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            },
            {
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              "version": "5.10.270",
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              "version": "5.15.221",
              "versionType": "semver",
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            },
            {
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/sched/sch_teql.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-17T17:16:56.073",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/00d8a387b23b7831ad9919256a6b9caaa10f19c3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/012559cf3c67ce8825a31d4f66b040b6fbaf775e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/0cd75037948567193f7f5767176538822ce23873",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1360bc93f5be1be3cf937ebea667b3418dd30a79",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/96bc345a3f17543d0d92ada609e02198d6380e26",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/aa39a790d56b40bfcf3861653ceb46a3a113adb6",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d453bf439ef230b5743afc25e194adacca8c6e43",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/dc4b95b8fee95113587e93ca116356032d271371",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_teql: restore skb->dev on the slave failure path\n\nteql_master_xmit() sets skb->dev = slave before calling the slave's\nndo_start_xmit(), but never restores it when that transmit fails. The\nskb then walks on to the next slave still pointing at the previous one.\n\nIf a later slave has no resolved neighbour, teql_resolve() hands the skb\nto neigh_event_send(), which queues it on that neighbour's arp_queue\nwith the stale skb->dev. skb->dev holds no reference, so deleting the\nprevious slave frees the net_device while the skb is still queued.\nWhatever runs next on that skb - arp_error_report() on timeout, or\nneigh_direct_output() -> dev_queue_xmit() once the neighbour resolves -\ncauses a UAF like the one below:\n\nBUG: KASAN: slab-use-after-free in __icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\nRead of size 4 at addr ffff888106e100b0 by task flood_packet/527\nCPU: 0 UID: 0 PID: 527 Comm: flood_packet Not tainted 7.2.0-rc6-g594d90519502 #1 PREEMPT(lazy)\nHardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nCall Trace:\n<IRQ>\ndump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)\nprint_report (mm/kasan/report.c:378 mm/kasan/report.c:482)\n? __pfx__raw_spin_lock_irqsave (./include/asm-generic/qrwlock.h:122 (discriminator 4))\n? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\nkasan_report (mm/kasan/report.c:595)\n? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\n__icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\n[...]\nipv4_link_failure (net/ipv4/route.c:1251 net/ipv4/route.c:1258)\n? __pfx_ipv4_link_failure (./include/linux/skbuff.h:4327)\n? _raw_write_lock (./include/linux/instrumented.h:55 ./include/linux/atomic/atomic-instrumented.h:1301 ./include/asm-generic/qrwlock.h:98 ./include/linux/rwlock_api_smp.h:230 kernel/locking/spinlock.c:304)\n? __pfx__raw_write_lock (kernel/locking/spinlock.c:175)\narp_error_report (./include/net/dst.h:438 net/ipv4/arp.c:296)\nneigh_invalidate (net/core/neighbour.c:1077)\nneigh_timer_handler (net/core/neighbour.c:1169)\n[...]\nAllocated by task 505:\nkasan_save_stack (mm/kasan/common.c:57)\nkasan_save_track (mm/kasan/common.c:78)\n__kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)\n__kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5334 mm/slub.c:6905)\nalloc_netdev_mqs (net/core/dev.c:12055 (discriminator 2))\nrtnl_create_link (net/core/rtnetlink.c:3721)\nrtnl_newlink (net/core/rtnetlink.c:3903 net/core/rtnetlink.c:4044 net/core/rtnetlink.c:4159)\nrtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n[...]\nFreed by task 536:\nkasan_save_stack (mm/kasan/common.c:57)\nkasan_save_track (mm/kasan/common.c:78)\nkasan_save_free_info (mm/kasan/generic.c:584)\n__kasan_slab_free (mm/kasan/common.c:253 mm/kasan/common.c:285)\nkfree (./include/linux/kasan.h:235 mm/slub.c:2677 mm/slub.c:6377 mm/slub.c:6692)\ndevice_release (drivers/base/core.c:2636)\nkobject_put (lib/kobject.c:689 lib/kobject.c:720 ./include/linux/kref.h:65 lib/kobject.c:737)\nnetdev_run_todo (net/core/dev.c:11756)\nrtnl_dellink (net/core/rtnetlink.c:157 ./include/linux/rtnetlink.h:135 net/core/rtnetlink.c:3651)\nrtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n[...]\n\nFix this by restoring skb->dev to the master at the end of each slave's\niteration."
    }
  ],
  "lastModified": "2026-09-18T18:17:40.850",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}