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CVE-2026-74742

Estado: RecibidaAlta (7.5)—

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

veth: fix queue index used to wake the peer txq in veth_poll

veth_poll() derives the index of the peer TX queue to wake from rq->xdp_rxq.queue_index. That field is only initialized by xdp_rxq_info_reg() in veth_enable_xdp_range(), which runs only when an XDP program is attached. On the plain GRO/NAPI path (veth_napi_enable_range()) xdp_rxq_info_reg() is never called, so queue_index stays 0 for every queue, as priv->rq is zero-allocated.

So in a multi-queue setup with GRO enabled and no XDP program attached, every NAPI instance looks at the peer's TX queue 0.

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If veth_xmit() stops peer TX queue 1 because the ptr_ring is full (NETDEV_TX_BUSY), nothing ever wakes it again: the poller draining queue 1 wakes queue 0 instead. veth implements no ndo_tx_timeout, so the netdev watchdog does not kick in either, and the queue stays stopped indefinitely.

Derive the index from the position of the rq within priv->rq instead, which is correct regardless of whether XDP was ever enabled.

Scripts to reproduce the stall are available at https://github.com/netoptimizer/veth-backpressure-performance-testing

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

Filter Network TrafficVulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkApplication 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 KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-74742",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "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": "9fe31b3f314534e238aa6d0b6fb492134cbcf8be",
              "lessThan": "b662a1fb4f3a5ea19bac24eea8315b1d05be51e7",
              "versionType": "git"
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            {
              "status": "affected",
              "version": "dc82a33297fc2c58cb0b2b008d728668d45c0f6a",
              "lessThan": "73f8dd22b1e533a99ecc3f9b5de6c6daccaecace",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "dc82a33297fc2c58cb0b2b008d728668d45c0f6a",
              "lessThan": "90bb11fb29d3c55a2c46dc7c386d096b286e7fcf",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "dc82a33297fc2c58cb0b2b008d728668d45c0f6a",
              "lessThan": "60db47f02bfa2aa688938aa199117ec4f8e31d23",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6.12.61",
              "lessThan": "6.12.105",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "drivers/net/veth.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.16",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.105",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.46",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.10",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/net/veth.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-26T15:16:52.990",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/60db47f02bfa2aa688938aa199117ec4f8e31d23",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/73f8dd22b1e533a99ecc3f9b5de6c6daccaecace",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/90bb11fb29d3c55a2c46dc7c386d096b286e7fcf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b662a1fb4f3a5ea19bac24eea8315b1d05be51e7",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: fix queue index used to wake the peer txq in veth_poll\n\nveth_poll() derives the index of the peer TX queue to wake from\nrq->xdp_rxq.queue_index. That field is only initialized by\nxdp_rxq_info_reg() in veth_enable_xdp_range(), which runs only when an\nXDP program is attached. On the plain GRO/NAPI path\n(veth_napi_enable_range()) xdp_rxq_info_reg() is never called, so\nqueue_index stays 0 for every queue, as priv->rq is zero-allocated.\n\nSo in a multi-queue setup with GRO enabled and no XDP program attached,\nevery NAPI instance looks at the peer's TX queue 0. If veth_xmit() stops\npeer TX queue 1 because the ptr_ring is full (NETDEV_TX_BUSY), nothing\never wakes it again: the poller draining queue 1 wakes queue 0 instead.\nveth implements no ndo_tx_timeout, so the netdev watchdog does not kick\nin either, and the queue stays stopped indefinitely.\n\nDerive the index from the position of the rq within priv->rq instead,\nwhich is correct regardless of whether XDP was ever enabled.\n\nScripts to reproduce the stall are available at\nhttps://github.com/netoptimizer/veth-backpressure-performance-testing"
    }
  ],
  "lastModified": "2026-08-27T06:17:23.867",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}