« Volver al listado

CVE-2026-74310

Estado: RecibidaCrítica (9.3)—

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

vhost/net: complete zerocopy ubufs only once

vhost-net initializes one ubuf_info per outstanding zerocopy TX descriptor and hands it to the backend socket. The networking stack may then clone a zerocopy skb before all skb references are released. For example, batman-adv fragmentation reaches skb_split(), which calls skb_zerocopy_clone() and increments the same ubuf_info refcount.

vhost_zerocopy_complete() currently treats every ubuf callback as a completed vhost descriptor.

Leer descripción completaMostrar menos

It dereferences ubuf->ctx, writes the descriptor completion state, and drops the vhost_net_ubuf_ref even when the callback only releases a cloned skb reference. A backend reset can therefore wait for and free the vhost_net_ubuf_ref while another cloned skb still carries the same ubuf_info. A later completion then dereferences the freed ubufs pointer.

The freed object was allocated from vhost_net_ioctl() while setting the backend and freed through kfree_rcu()/kvfree_rcu_bulk after backend removal, while delayed skb completion still reached vhost_zerocopy_complete().

Honor the generic ubuf_info refcount before touching vhost state, and run the vhost descriptor completion only for the final ubuf reference. This matches the msg_zerocopy_complete() ownership rule for cloned zerocopy skbs.

Detalles técnicos trazas, registros y código del informe original
KASAN reports the stale completion as:

  BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x1d7/0x1f0
  BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x101/0x1f0
  vhost_zerocopy_complete
  skb_copy_ubufs
  __dev_forward_skb2
  veth_xmit

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.

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence ProgramExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate 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 KernelAI

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-74310",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 9.3,
          "attackVector": "LOCAL",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 6,
        "exploitabilityScore": 2.5
      }
    ]
  },
  "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": "bab632d69ee48a106e779b60cc01adfe80a72807",
              "lessThan": "ea71f873423fb73e66ad88936d6759ac0ad4aa53",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bab632d69ee48a106e779b60cc01adfe80a72807",
              "lessThan": "6445b945024f4c7675ae5352b2d5885cb1deea71",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bab632d69ee48a106e779b60cc01adfe80a72807",
              "lessThan": "a9f8a1d2e3ff511eafd4c5462481950c2f4d2b5d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bab632d69ee48a106e779b60cc01adfe80a72807",
              "lessThan": "321c73baf54d971ce3771fea275c98a247f7ee35",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bab632d69ee48a106e779b60cc01adfe80a72807",
              "lessThan": "c069437924663539a93a1e5afe90838d9ccee284",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bab632d69ee48a106e779b60cc01adfe80a72807",
              "lessThan": "8f6898fe80794f2d7c3d38c1158c806e4074a1c4",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/vhost/net.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.1"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "3.1",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/vhost/net.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T06:22:30.987",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/321c73baf54d971ce3771fea275c98a247f7ee35",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6445b945024f4c7675ae5352b2d5885cb1deea71",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8f6898fe80794f2d7c3d38c1158c806e4074a1c4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a9f8a1d2e3ff511eafd4c5462481950c2f4d2b5d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c069437924663539a93a1e5afe90838d9ccee284",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ea71f873423fb73e66ad88936d6759ac0ad4aa53",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost/net: complete zerocopy ubufs only once\n\nvhost-net initializes one ubuf_info per outstanding zerocopy TX\ndescriptor and hands it to the backend socket.  The networking stack may\nthen clone a zerocopy skb before all skb references are released.  For\nexample, batman-adv fragmentation reaches skb_split(), which calls\nskb_zerocopy_clone() and increments the same ubuf_info refcount.\n\nvhost_zerocopy_complete() currently treats every ubuf callback as a\ncompleted vhost descriptor.  It dereferences ubuf->ctx, writes the\ndescriptor completion state, and drops the vhost_net_ubuf_ref even when\nthe callback only releases a cloned skb reference.  A backend reset can\ntherefore wait for and free the vhost_net_ubuf_ref while another cloned\nskb still carries the same ubuf_info.  A later completion then\ndereferences the freed ubufs pointer.\n\nKASAN reports the stale completion as:\n\n  BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x1d7/0x1f0\n  BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x101/0x1f0\n  vhost_zerocopy_complete\n  skb_copy_ubufs\n  __dev_forward_skb2\n  veth_xmit\n\nThe freed object was allocated from vhost_net_ioctl() while setting the\nbackend and freed through kfree_rcu()/kvfree_rcu_bulk after backend\nremoval, while delayed skb completion still reached\nvhost_zerocopy_complete().\n\nHonor the generic ubuf_info refcount before touching vhost state, and run\nthe vhost descriptor completion only for the final ubuf reference.  This\nmatches the msg_zerocopy_complete() ownership rule for cloned zerocopy\nskbs."
    }
  ],
  "lastModified": "2026-08-17T06:19:25.200",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}