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CVE-2026-80615

Estado: RecibidaAlta (8.2)—

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

net: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone

kmalloc_flex() in metadata_dst_alloc() sets __counted_by for the structure to the options_len, which is then initialized to zero. Later, we're initializing the structure by copying the tunnel info together with the options, and this triggers a warning for a potential memcpy overflow, since the compiler estimates that the options can't fit into the structure, even though the memory for them is actually allocated.

The issue is triggered when built with clang and source fortification.

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Fix that by doing the copy in two stages: first - the main data with the options_len, then the options. This way the correct length should be known at the time of the copy.

It would be better if the options_len never changed after allocation, but the allocation code is a little separate from the initialization and it would be awkward and potentially dangerous to return a struct with options_len set to a non-zero value from the metadata_dst_alloc().

Another option would be to use ip_tunnel_info_opts_set(), but it is doing too many unnecessary operations for the use case here.

Detalles técnicos trazas, registros y código del informe original
 memcpy: detected buffer overflow: 104 byte write of buffer size 96
 WARNING: CPU: X PID: Y at lib/string_helpers.c:1036 __fortify_report
  skb_tunnel_info_unclone+0x179/0x190
  geneve_xmit+0x7fe/0xe00

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.

Vector AV:N/AC:L/PR:N indica acceso remoto sin autenticación (T1190), pero la vulnerabilidad es un falso positivo de buffer overflow en fortificación: requiere compilación específica clang+fortification. El impacto es DoS por panic del kernel ante la advertencia de fortify (T1499.004).

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

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-2026-80615",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.2,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 4.2,
        "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": "69050f8d6d075dc01af7a5f2f550a8067510366f",
              "lessThan": "7ce31739fe88a558370135db95bbeec1e7ddfc29",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "69050f8d6d075dc01af7a5f2f550a8067510366f",
              "lessThan": "4c6d43db2a4d2cef3921e885cf34798f790d34ea",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "include/net/dst_metadata.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "7.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "include/net/dst_metadata.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-28T08:16:45.523",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/4c6d43db2a4d2cef3921e885cf34798f790d34ea",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7ce31739fe88a558370135db95bbeec1e7ddfc29",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone\n\nkmalloc_flex() in metadata_dst_alloc() sets __counted_by for the\nstructure to the options_len, which is then initialized to zero.\nLater, we're initializing the structure by copying the tunnel info\ntogether with the options, and this triggers a warning for a potential\nmemcpy overflow, since the compiler estimates that the options can't\nfit into the structure, even though the memory for them is actually\nallocated.\n\n memcpy: detected buffer overflow: 104 byte write of buffer size 96\n WARNING: CPU: X PID: Y at lib/string_helpers.c:1036 __fortify_report\n  skb_tunnel_info_unclone+0x179/0x190\n  geneve_xmit+0x7fe/0xe00\n\nThe issue is triggered when built with clang and source fortification.\n\nFix that by doing the copy in two stages: first - the main data with\nthe options_len, then the options.  This way the correct length should\nbe known at the time of the copy.\n\nIt would be better if the options_len never changed after allocation,\nbut the allocation code is a little separate from the initialization\nand it would be awkward and potentially dangerous to return a struct\nwith options_len set to a non-zero value from the metadata_dst_alloc().\n\nAnother option would be to use ip_tunnel_info_opts_set(), but it is\ndoing too many unnecessary operations for the use case here."
    }
  ],
  "lastModified": "2026-08-29T07:16:46.377",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}