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CVE-2026-97937

Estado: RecibidaAlta (7.8)—

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

ftrace: fork: Initialize function graph state before copy_exec_state()

dup_task_struct() copies the parent's task_struct, including ret_stack. ftrace_graph_init_task() clears the copied function graph state, but it currently runs after copy_exec_state().

For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state. If that allocation fails, copy_process() reaches bad_fork_free and free_task() calls ftrace_graph_exit_task(). Since the child still carries the parent's ret_stack pointer, the unwind frees the parent's active function graph return stack. The parent subsequently accesses freed memory from function_graph_enter_regs().

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Initialize the child function graph state immediately after dup_task_struct(), before the first fallible operation.

Detalles técnicos trazas, registros y código del informe original
KASAN reports:

[   22.190920] ==================================================================
[   22.195899] BUG: KASAN: slab-use-after-free in function_graph_enter_regs+0xa76/0xb90
[   22.200747] Write of size 8 at addr ff110000054dc0a8 by task repro/1
[   22.205134]
[   22.210770] CPU: 0 UID: 0 PID: 1 Comm: repro Not tainted 7.2.0-07732-g9328b3b03bdc-dirty #3 PREEMPT(lazy)
[   22.212576] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   22.213750] Call Trace:
[   22.215271]  <TASK>
[   22.216242]  ? ftrace_stub_direct_tramp+0x10/0x10
[   22.217774]  dump_stack_lvl+0x4e/0x70
[   22.220531]  print_report+0x157/0x4b4
[   22.223202]  ? fixup_red_left+0x9/0x30
[   22.224407]  ? complete_report_info+0x83/0x110
[   22.226679]  ? function_graph_enter_regs+0xa76/0xb90
[   22.228084]  kasan_report+0xce/0x100
[   22.230109]  ? function_graph_enter_regs+0xa76/0xb90
[   22.232860]  ? stack_trace_save+0x4/0xd0
[   22.234156]  function_graph_enter_regs+0xa76/0xb90
[   22.236090]  ? kasan_save_stack+0x30/0x50
[   22.237752]  ? __pfx_function_graph_enter_regs+0x10/0x10
[   22.238694]  ? ring_buffer_lock_reserve+0x345/0xf80
[   22.239628]  ? stack_trace_save+0x4/0xd0
[   22.242121]  ? stack_trace_save+0x4/0xd0
[   22.243588]  ftrace_graph_func+0xda/0x160
[   22.245362]  ? ftrace_stub_direct_tramp+0x10/0x10
[   22.246520]  0xffffffffa0000095
[   22.250528]  ? stack_trace_save+0x9/0xd0
[   22.251757]  ? ring_buffer_unlock_commit+0x11d/0x5c0
[   22.253152]  stack_trace_save+0x9/0xd0
[   22.254264]  kasan_save_stack+0x30/0x50
[   22.273631]  kasan_save_track+0x14/0x30
[   22.276763]  kasan_save_free_info+0x3b/0x70
[   22.278296]  __kasan_slab_free+0x43/0x70
[   22.280157]  kmem_cache_free+0xbf/0x3b0
[   22.282963]  ? ftrace_stub_direct_tramp+0x10/0x10
[   22.284001]  free_task+0xa2/0x160
[   22.285699]  ? ftrace_stub_direct_tramp+0x10/0x10
[   22.286752]  copy_process+0x2aae/0x7bc0

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 local (AV:L/PR:L) que permite use-after-free al manipular el estado de fork en el kernel; permite lectura de memoria liberada (KASAN) y potencial DoS por corrupción de memoria.

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)

Mostrar
{
  "id": "CVE-2026-97937",
  "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": "6b1c66c9cca99bf00386481c7b2aa7394c26d8b8",
              "lessThan": "1fadebbbf31f65beba353fa9d1373bf183e03fed",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6b1c66c9cca99bf00386481c7b2aa7394c26d8b8",
              "lessThan": "08cacffeef8f64f1a222c93467ca84f24a46c953",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "kernel/fork.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.2"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "7.2",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "kernel/fork.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-25T11:17:21.080",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/08cacffeef8f64f1a222c93467ca84f24a46c953",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1fadebbbf31f65beba353fa9d1373bf183e03fed",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nftrace: fork: Initialize function graph state before copy_exec_state()\n\ndup_task_struct() copies the parent's task_struct, including ret_stack.\nftrace_graph_init_task() clears the copied function graph state, but it\ncurrently runs after copy_exec_state().\n\nFor non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state.\nIf that allocation fails, copy_process() reaches bad_fork_free and\nfree_task() calls ftrace_graph_exit_task(). Since the child still carries\nthe parent's ret_stack pointer, the unwind frees the parent's active\nfunction graph return stack. The parent subsequently accesses freed memory\nfrom function_graph_enter_regs().\n\nKASAN reports:\n\n[   22.190920] ==================================================================\n[   22.195899] BUG: KASAN: slab-use-after-free in function_graph_enter_regs+0xa76/0xb90\n[   22.200747] Write of size 8 at addr ff110000054dc0a8 by task repro/1\n[   22.205134]\n[   22.210770] CPU: 0 UID: 0 PID: 1 Comm: repro Not tainted 7.2.0-07732-g9328b3b03bdc-dirty #3 PREEMPT(lazy)\n[   22.212576] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[   22.213750] Call Trace:\n[   22.215271]  <TASK>\n[   22.216242]  ? ftrace_stub_direct_tramp+0x10/0x10\n[   22.217774]  dump_stack_lvl+0x4e/0x70\n[   22.220531]  print_report+0x157/0x4b4\n[   22.223202]  ? fixup_red_left+0x9/0x30\n[   22.224407]  ? complete_report_info+0x83/0x110\n[   22.226679]  ? function_graph_enter_regs+0xa76/0xb90\n[   22.228084]  kasan_report+0xce/0x100\n[   22.230109]  ? function_graph_enter_regs+0xa76/0xb90\n[   22.232860]  ? stack_trace_save+0x4/0xd0\n[   22.234156]  function_graph_enter_regs+0xa76/0xb90\n[   22.236090]  ? kasan_save_stack+0x30/0x50\n[   22.237752]  ? __pfx_function_graph_enter_regs+0x10/0x10\n[   22.238694]  ? ring_buffer_lock_reserve+0x345/0xf80\n[   22.239628]  ? stack_trace_save+0x4/0xd0\n[   22.242121]  ? stack_trace_save+0x4/0xd0\n[   22.243588]  ftrace_graph_func+0xda/0x160\n[   22.245362]  ? ftrace_stub_direct_tramp+0x10/0x10\n[   22.246520]  0xffffffffa0000095\n[   22.250528]  ? stack_trace_save+0x9/0xd0\n[   22.251757]  ? ring_buffer_unlock_commit+0x11d/0x5c0\n[   22.253152]  stack_trace_save+0x9/0xd0\n[   22.254264]  kasan_save_stack+0x30/0x50\n[   22.273631]  kasan_save_track+0x14/0x30\n[   22.276763]  kasan_save_free_info+0x3b/0x70\n[   22.278296]  __kasan_slab_free+0x43/0x70\n[   22.280157]  kmem_cache_free+0xbf/0x3b0\n[   22.282963]  ? ftrace_stub_direct_tramp+0x10/0x10\n[   22.284001]  free_task+0xa2/0x160\n[   22.285699]  ? ftrace_stub_direct_tramp+0x10/0x10\n[   22.286752]  copy_process+0x2aae/0x7bc0\n\nInitialize the child function graph state immediately after\ndup_task_struct(), before the first fallible operation."
    }
  ],
  "lastModified": "2026-09-25T15:18:02.577",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}