CVE-2026-74256

Estado: RecibidaAlta (8.4)—

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

bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check

start and len are u32, so

evaluates start + len in 32-bit and wraps before storing it in last. The bounds check

can then be passed with an out-of-range start/len, after which the pop loop runs off the end of the scatterlist and sk_msg_shift_left() calls put_page() on the empty msg->sg.end slot:

Widen the addition with a (u64) cast so the bound is evaluated in 64-bit and a len near U32_MAX no longer wraps below msg->sg.size.

While here, change pop from int to u32. It counts bytes against the unsigned scatterlist lengths and can never be negative, so the signed type only invites sign-confusion in the pop loop.

Detalles técnicos trazas, registros y código del informe original

	u64 last = start + len;

	if (start >= offset + l || last > msg->sg.size)
		return -EINVAL;

  Oops: general protection fault, probably for non-canonical address
  0xdffffc0000000001: 0000 [#1] SMP KASAN PTI
  KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
  RIP: 0010:sk_msg_shift_left net/core/filter.c:2957 [inline]
  RIP: 0010:____bpf_msg_pop_data net/core/filter.c:3103 [inline]
  RIP: 0010:bpf_msg_pop_data+0x753/0x1a10 net/core/filter.c:2984
  Call Trace:
   <TASK>
   bpf_prog_4cc92c278f4d5d56+0x1b1/0x1e8
   bpf_prog_run_pin_on_cpu+0x107/0x320 include/linux/filter.h:746
   sk_psock_msg_verdict+0x357/0x7f0 net/core/skmsg.c:934
   tcp_bpf_send_verdict net/ipv4/tcp_bpf.c:420 [inline]
   tcp_bpf_sendmsg+0x766/0x1ae0 net/ipv4/tcp_bpf.c:583
   __sock_sendmsg+0x153/0x1c0 net/socket.c:802
   __sys_sendto+0x326/0x430 net/socket.c:2265
   __x64_sys_sendto+0xe3/0x100 net/socket.c:2268
   do_syscall_64+0x14c/0x480
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   </TASK>

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 8.4

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.20%
Percentil entre todas las CVEs puntuadas: 8
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 escalation85 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %
Impacto secundarioT1546 Event Triggered Executionprivilege escalation · persistence60 %

Vulnerabilidad de desbordamiento de enteros en código kernel de Linux accesible localmente (AV:L, PR:N, UI:N). Permite bypass de validación de límites causando corrupción de memoria y panic del kernel (DoS). Escalada implícita por ejecución con privilegios de kernel.

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

Update Software Threat Intelligence Program Privileged Account Management Filter Network Traffic Execution Prevention Application Isolation and Sandboxing

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-2026-74256",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.4,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
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        "impactScore": 5.9,
        "exploitabilityScore": 2.5
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              "version": "5.15.212",
              "versionType": "semver",
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              "version": "6.1.178",
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              "version": "6.6.145",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
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              "version": "6.12.97",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
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              "version": "6.18.40",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
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              "version": "7.1.5",
              "versionType": "semver",
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            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
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          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T06:22:24.743",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/17eb9832a10db2f7a80cb429ca2bc5038445a943",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/fe09dd288722f1c749b7506c0b3e7841a7d85027",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check\n\nstart and len are u32, so\n\n\tu64 last = start + len;\n\nevaluates start + len in 32-bit and wraps before storing it in last.\nThe bounds check\n\n\tif (start >= offset + l || last > msg->sg.size)\n\t\treturn -EINVAL;\n\ncan then be passed with an out-of-range start/len, after which the pop\nloop runs off the end of the scatterlist and sk_msg_shift_left() calls\nput_page() on the empty msg->sg.end slot:\n\n  Oops: general protection fault, probably for non-canonical address\n  0xdffffc0000000001: 0000 [#1] SMP KASAN PTI\n  KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]\n  RIP: 0010:sk_msg_shift_left net/core/filter.c:2957 [inline]\n  RIP: 0010:____bpf_msg_pop_data net/core/filter.c:3103 [inline]\n  RIP: 0010:bpf_msg_pop_data+0x753/0x1a10 net/core/filter.c:2984\n  Call Trace:\n   <TASK>\n   bpf_prog_4cc92c278f4d5d56+0x1b1/0x1e8\n   bpf_prog_run_pin_on_cpu+0x107/0x320 include/linux/filter.h:746\n   sk_psock_msg_verdict+0x357/0x7f0 net/core/skmsg.c:934\n   tcp_bpf_send_verdict net/ipv4/tcp_bpf.c:420 [inline]\n   tcp_bpf_sendmsg+0x766/0x1ae0 net/ipv4/tcp_bpf.c:583\n   __sock_sendmsg+0x153/0x1c0 net/socket.c:802\n   __sys_sendto+0x326/0x430 net/socket.c:2265\n   __x64_sys_sendto+0xe3/0x100 net/socket.c:2268\n   do_syscall_64+0x14c/0x480\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n   </TASK>\n\nWiden the addition with a (u64) cast so the bound is evaluated in\n64-bit and a len near U32_MAX no longer wraps below msg->sg.size.\n\nWhile here, change pop from int to u32. It counts bytes against the\nunsigned scatterlist lengths and can never be negative, so the signed\ntype only invites sign-confusion in the pop loop."
    }
  ],
  "lastModified": "2026-08-17T06:19:18.920",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}