CVE-2023-54206

Estado: AplazadaAlta (7.8)—

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

net/sched: flower: fix filter idr initialization

The cited commit moved idr initialization too early in fl_change() which allows concurrent users to access the filter that is still being initialized and is in inconsistent state, which, in turn, can cause NULL pointer dereference [0]. Since there is no obvious way to fix the ordering without reverting the whole cited commit, alternative approach taken to first insert NULL pointer into idr in order to allocate the handle but still cause fl_get() to return NULL and prevent concurrent users from seeing the filter while providing miss-to-action infrastructure with valid handle id early in fl_change().

Detalles técnicos trazas, registros y código del informe original

[  152.434728] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN
[  152.436163] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
[  152.437269] CPU: 4 PID: 3877 Comm: tc Not tainted 6.3.0-rc4+ #5
[  152.438110] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[  152.439644] RIP: 0010:fl_dump_key+0x8b/0x1d10 [cls_flower]
[  152.440461] Code: 01 f2 02 f2 c7 40 08 04 f2 04 f2 c7 40 0c 04 f3 f3 f3 65 48 8b 04 25 28 00 00 00 48 89 84 24 00 01 00 00 48 89 c8 48 c1 e8 03 <0f> b6 04 10 84 c0 74 08 3c 03 0f 8e 98 19 00 00 8b 13 85 d2 74 57
[  152.442885] RSP: 0018:ffff88817a28f158 EFLAGS: 00010246
[  152.443851] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[  152.444826] RDX: dffffc0000000000 RSI: ffffffff8500ae80 RDI: ffff88810a987900
[  152.445791] RBP: ffff888179d88240 R08: ffff888179d8845c R09: ffff888179d88240
[  152.446780] R10: ffffed102f451e48 R11: 00000000fffffff2 R12: ffff88810a987900
[  152.447741] R13: ffffffff8500ae80 R14: ffff88810a987900 R15: ffff888149b3c738
[  152.448756] FS:  00007f5eb2a34800(0000) GS:ffff88881ec00000(0000) knlGS:0000000000000000
[  152.449888] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  152.450685] CR2: 000000000046ad19 CR3: 000000010b0bd006 CR4: 0000000000370ea0
[  152.451641] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  152.452628] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  152.453588] Call Trace:
[  152.454032]  <TASK>
[  152.454447]  ? netlink_sendmsg+0x7a1/0xcb0
[  152.455109]  ? sock_sendmsg+0xc5/0x190
[  152.455689]  ? ____sys_sendmsg+0x535/0x6b0
[  152.456320]  ? ___sys_sendmsg+0xeb/0x170
[  152.456916]  ? do_syscall_64+0x3d/0x90
[  152.457529]  ? entry_SYSCALL_64_after_hwframe+0x46/0xb0
[  152.458321]  ? ___sys_sendmsg+0xeb/0x170
[  152.458958]  ? __sys_sendmsg+0xb5/0x140
[  152.459564]  ? do_syscall_64+0x3d/0x90
[  152.460122]  ? entry_SYSCALL_64_after_hwframe+0x46/0xb0
[  152.460852]  ? fl_dump_key_options.part.0+0xea0/0xea0 [cls_flower]
[  152.461710]  ? _raw_spin_lock+0x7a/0xd0
[  152.462299]  ? _raw_read_lock_irq+0x30/0x30
[  152.462924]  ? nla_put+0x15e/0x1c0
[  152.463480]  fl_dump+0x228/0x650 [cls_flower]
[  152.464112]  ? fl_tmplt_dump+0x210/0x210 [cls_flower]
[  152.464854]  ? __kmem_cache_alloc_node+0x1a7/0x330
[  152.465592]  ? nla_put+0x15e/0x1c0
[  152.466160]  tcf_fill_node+0x515/0x9a0
[  152.466766]  ? tc_setup_offload_action+0xf0/0xf0
[  152.467463]  ? __alloc_skb+0x13c/0x2a0
[  152.468067]  ? __build_skb_around+0x330/0x330
[  152.468814]  ? fl_get+0x107/0x1a0 [cls_flower]
[  152.469503]  tc_del_tfilter+0x718/0x1330
[  152.470115]  ? is_bpf_text_address+0xa/0x20
[  152.470765]  ? tc_ctl_chain+0xee0/0xee0
[  152.471335]  ? __kernel_text_address+0xe/0x30
[  152.471948]  ? unwind_get_return_address+0x56/0xa0
[  152.472639]  ? __thaw_task+0x150/0x150
[  152.473218]  ? arch_stack_walk+0x98/0xf0
[  152.473839]  ? __stack_depot_save+0x35/0x4c0
[  152.474501]  ? stack_trace_save+0x91/0xc0
[  152.475119]  ? security_capable+0x51/0x90
[  152.475741]  rtnetlink_rcv_msg+0x2c1/0x9d0
[  152.476387]  ? rtnl_calcit.isra.0+0x2b0/0x2b0
[  152.477042]
---truncated---

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.14%
Percentil entre todas las CVEs puntuadas: 3
Fecha de la puntuación: 6/10/2026

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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation95 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %
Impacto secundarioT1529 System Shutdown/Rebootimpact70 %

Vulnerabilidad de kernel Linux (AV:L/PR:L/UI:N) que causa NULL pointer dereference y crash del sistema. Requiere acceso local con privilegios, escalando mediante race condition en flower filter initialization. Impacto: DoS por crash de kernel y potencial reinicio del sistema.

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

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

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

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2023-54206",
  "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": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "08a0063df3aed8d76a4034279117db12dbc1050f",
              "lessThan": "253a3a324e0ebc2825de76a0f5f17b8383b2023d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "08a0063df3aed8d76a4034279117db12dbc1050f",
              "lessThan": "dd4f6bbfa646f258e5bcdfac57a5c413d687f588",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/sched/cls_flower.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.3"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.3",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.3.3",
              "versionType": "semver",
              "lessThanOrEqual": "6.3.*"
            },
            {
              "status": "unaffected",
              "version": "6.4",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/sched/cls_flower.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-12-30T13:16:08.750",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/253a3a324e0ebc2825de76a0f5f17b8383b2023d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/dd4f6bbfa646f258e5bcdfac57a5c413d687f588",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: flower: fix filter idr initialization\n\nThe cited commit moved idr initialization too early in fl_change() which\nallows concurrent users to access the filter that is still being\ninitialized and is in inconsistent state, which, in turn, can cause NULL\npointer dereference [0]. Since there is no obvious way to fix the ordering\nwithout reverting the whole cited commit, alternative approach taken to\nfirst insert NULL pointer into idr in order to allocate the handle but\nstill cause fl_get() to return NULL and prevent concurrent users from\nseeing the filter while providing miss-to-action infrastructure with valid\nhandle id early in fl_change().\n\n[  152.434728] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN\n[  152.436163] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]\n[  152.437269] CPU: 4 PID: 3877 Comm: tc Not tainted 6.3.0-rc4+ #5\n[  152.438110] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\n[  152.439644] RIP: 0010:fl_dump_key+0x8b/0x1d10 [cls_flower]\n[  152.440461] Code: 01 f2 02 f2 c7 40 08 04 f2 04 f2 c7 40 0c 04 f3 f3 f3 65 48 8b 04 25 28 00 00 00 48 89 84 24 00 01 00 00 48 89 c8 48 c1 e8 03 <0f> b6 04 10 84 c0 74 08 3c 03 0f 8e 98 19 00 00 8b 13 85 d2 74 57\n[  152.442885] RSP: 0018:ffff88817a28f158 EFLAGS: 00010246\n[  152.443851] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000\n[  152.444826] RDX: dffffc0000000000 RSI: ffffffff8500ae80 RDI: ffff88810a987900\n[  152.445791] RBP: ffff888179d88240 R08: ffff888179d8845c R09: ffff888179d88240\n[  152.446780] R10: ffffed102f451e48 R11: 00000000fffffff2 R12: ffff88810a987900\n[  152.447741] R13: ffffffff8500ae80 R14: ffff88810a987900 R15: ffff888149b3c738\n[  152.448756] FS:  00007f5eb2a34800(0000) GS:ffff88881ec00000(0000) knlGS:0000000000000000\n[  152.449888] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[  152.450685] CR2: 000000000046ad19 CR3: 000000010b0bd006 CR4: 0000000000370ea0\n[  152.451641] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n[  152.452628] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n[  152.453588] Call Trace:\n[  152.454032]  <TASK>\n[  152.454447]  ? netlink_sendmsg+0x7a1/0xcb0\n[  152.455109]  ? sock_sendmsg+0xc5/0x190\n[  152.455689]  ? ____sys_sendmsg+0x535/0x6b0\n[  152.456320]  ? ___sys_sendmsg+0xeb/0x170\n[  152.456916]  ? do_syscall_64+0x3d/0x90\n[  152.457529]  ? entry_SYSCALL_64_after_hwframe+0x46/0xb0\n[  152.458321]  ? ___sys_sendmsg+0xeb/0x170\n[  152.458958]  ? __sys_sendmsg+0xb5/0x140\n[  152.459564]  ? do_syscall_64+0x3d/0x90\n[  152.460122]  ? entry_SYSCALL_64_after_hwframe+0x46/0xb0\n[  152.460852]  ? fl_dump_key_options.part.0+0xea0/0xea0 [cls_flower]\n[  152.461710]  ? _raw_spin_lock+0x7a/0xd0\n[  152.462299]  ? _raw_read_lock_irq+0x30/0x30\n[  152.462924]  ? nla_put+0x15e/0x1c0\n[  152.463480]  fl_dump+0x228/0x650 [cls_flower]\n[  152.464112]  ? fl_tmplt_dump+0x210/0x210 [cls_flower]\n[  152.464854]  ? __kmem_cache_alloc_node+0x1a7/0x330\n[  152.465592]  ? nla_put+0x15e/0x1c0\n[  152.466160]  tcf_fill_node+0x515/0x9a0\n[  152.466766]  ? tc_setup_offload_action+0xf0/0xf0\n[  152.467463]  ? __alloc_skb+0x13c/0x2a0\n[  152.468067]  ? __build_skb_around+0x330/0x330\n[  152.468814]  ? fl_get+0x107/0x1a0 [cls_flower]\n[  152.469503]  tc_del_tfilter+0x718/0x1330\n[  152.470115]  ? is_bpf_text_address+0xa/0x20\n[  152.470765]  ? tc_ctl_chain+0xee0/0xee0\n[  152.471335]  ? __kernel_text_address+0xe/0x30\n[  152.471948]  ? unwind_get_return_address+0x56/0xa0\n[  152.472639]  ? __thaw_task+0x150/0x150\n[  152.473218]  ? arch_stack_walk+0x98/0xf0\n[  152.473839]  ? __stack_depot_save+0x35/0x4c0\n[  152.474501]  ? stack_trace_save+0x91/0xc0\n[  152.475119]  ? security_capable+0x51/0x90\n[  152.475741]  rtnetlink_rcv_msg+0x2c1/0x9d0\n[  152.476387]  ? rtnl_calcit.isra.0+0x2b0/0x2b0\n[  152.477042]\n---truncated---"
    }
  ],
  "lastModified": "2026-08-04T11:16:36.730",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}