FKIE_CVE-2026-74665

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-10-14 13:10
Severity
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Summary
In the Linux kernel, the following vulnerability has been resolved: net: fix skb length accounting after generic XDP frag adjustment Generic XDP exposes non-linear skb fragments through an xdp_buff. If an XDP program adjusts the fragment area, bpf_prog_run_generic_xdp() copies xdp_frags_size back to skb->data_len but leaves skb->len containing the old fragment contribution. After a fragment shrink, this makes skb_headlen() larger than the actual linear area. In the reproduced UDP receive path, __skb_datagram_iter() copied 1024 bytes past the actual linear tail to userspace, starting at struct skb_shared_info. The copied bytes included the affected skb's nr_frags, xdp_frags_size and a kernel pointer from skb_shinfo(skb)->frags[0]. Real packet data was displaced by the same amount and truncated at the end. Subtract the old data_len before replacing it and add the new data_len afterwards, keeping skb->len and skb->data_len synchronized. A 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by 1024 bytes from its fragment area. Before the fix, all 10 runs produced corrupted payloads. After the fix, all 10 runs matched the expected payload exactly.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/33f2b2eb33d666ecac68031e0f31424fb70528db
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5f30f9c302cea1f2ebf97abe574c1826544223d7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/72468efcc089782fa047afddd10856b11a14ef5b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ea1ccd6d1c6370868e3b032a3fc575b9c397f2e1
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/dev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "72468efcc089782fa047afddd10856b11a14ef5b",
              "status": "affected",
              "version": "e6d5dbdd20aa6a86974af51deb9414cd2e7794cb",
              "versionType": "git"
            },
            {
              "lessThan": "5f30f9c302cea1f2ebf97abe574c1826544223d7",
              "status": "affected",
              "version": "e6d5dbdd20aa6a86974af51deb9414cd2e7794cb",
              "versionType": "git"
            },
            {
              "lessThan": "ea1ccd6d1c6370868e3b032a3fc575b9c397f2e1",
              "status": "affected",
              "version": "e6d5dbdd20aa6a86974af51deb9414cd2e7794cb",
              "versionType": "git"
            },
            {
              "lessThan": "33f2b2eb33d666ecac68031e0f31424fb70528db",
              "status": "affected",
              "version": "e6d5dbdd20aa6a86974af51deb9414cd2e7794cb",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/core/dev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "lessThan": "6.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: fix skb length accounting after generic XDP frag adjustment\n\nGeneric XDP exposes non-linear skb fragments through an xdp_buff. If an\nXDP program adjusts the fragment area, bpf_prog_run_generic_xdp() copies\nxdp_frags_size back to skb-\u003edata_len but leaves skb-\u003elen containing the\nold fragment contribution.\n\nAfter a fragment shrink, this makes skb_headlen() larger than the actual\nlinear area. In the reproduced UDP receive path, __skb_datagram_iter()\ncopied 1024 bytes past the actual linear tail to userspace, starting at\nstruct skb_shared_info. The copied bytes included the affected skb\u0027s\nnr_frags, xdp_frags_size and a kernel pointer from\nskb_shinfo(skb)-\u003efrags[0]. Real packet data was displaced by the same\namount and truncated at the end.\n\nSubtract the old data_len before replacing it and add the new data_len\nafterwards, keeping skb-\u003elen and skb-\u003edata_len synchronized.\n\nA 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by\n1024 bytes from its fragment area. Before the fix, all 10 runs produced\ncorrupted payloads. After the fix, all 10 runs matched the expected\npayload exactly."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet: correcci\u00f3n de la contabilidad de la longitud del skb despu\u00e9s del ajuste gen\u00e9rico de fragmentos XDP\n\nXDP gen\u00e9rico expone fragmentos de skb no lineales a trav\u00e9s de un xdp_buff. Si un programa XDP ajusta el \u00e1rea de fragmentos, bpf_prog_run_generic_xdp() copia xdp_frags_size de vuelta a skb -\u003e data_len pero deja skb -\u003e len conteniendo la antigua contribuci\u00f3n del fragmento.\n\nDespu\u00e9s de una reducci\u00f3n de fragmento, esto hace que skb_headlen() sea mayor que el \u00e1rea lineal real. En la ruta de recepci\u00f3n UDP reproducida, __skb_datagram_iter() copi\u00f3 1024 bytes m\u00e1s all\u00e1 de la cola lineal real al espacio de usuario, comenzando en struct skb_shared_info. Los bytes copiados inclu\u00edan nr_frags, xdp_frags_size del skb afectado y un puntero del kernel de skb_shinfo(skb) -\u003e frags[0]. Datos reales del paquete fueron desplazados por la misma cantidad y truncados al final.\n\nReste el data_len antiguo antes de reemplazarlo y a\u00f1ada el nuevo data_len despu\u00e9s, manteniendo skb -\u003e len y skb -\u003e data_len sincronizados.\n\nUn datagrama UDP de 60000 bytes en un par veth con MTU 64000 fue acortado en 1024 bytes de su \u00e1rea de fragmentos. Antes de la correcci\u00f3n, las 10 ejecuciones produjeron cargas \u00fatiles corruptas. Despu\u00e9s de la correcci\u00f3n, las 10 ejecuciones coincidieron exactamente con la carga \u00fatil esperada."
    }
  ],
  "id": "CVE-2026-74665",
  "lastModified": "2026-10-14T13:10:00.187",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:40.357",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/33f2b2eb33d666ecac68031e0f31424fb70528db"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5f30f9c302cea1f2ebf97abe574c1826544223d7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/72468efcc089782fa047afddd10856b11a14ef5b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ea1ccd6d1c6370868e3b032a3fc575b9c397f2e1"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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