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CVE-2025-39988

Estado: AplazadaAlta (7.8)—

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

can: etas_es58x: populate ndo_change_mtu() to prevent buffer overflow

Sending an PF_PACKET allows to bypass the CAN framework logic and to directly reach the xmit() function of a CAN driver. The only check which is performed by the PF_PACKET framework is to make sure that skb->len fits the interface's MTU.

Unfortunately, because the etas_es58x driver does not populate its net_device_ops->ndo_change_mtu(), it is possible for an attacker to configure an invalid MTU by doing, for example:

After doing so, the attacker could open a PF_PACKET socket using the ETH_P_CANXL protocol:

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to inject a malicious CAN XL frames. For example:

The CAN drivers' xmit() function are calling can_dev_dropped_skb() to check that the skb is valid, unfortunately under above conditions, the malicious packet is able to go through can_dev_dropped_skb() checks:

And so, es58x_start_xmit() receives a CAN XL frame which it is not able to correctly handle and will thus misinterpret it as a CAN(FD) frame.

This can result in a buffer overflow. For example, using the es581.4 variant, the frame will be dispatched to es581_4_tx_can_msg(), go through the last check at the beginning of this function:

and reach this line:

Here, cf->len corresponds to the flags field of the CAN XL frame. In our previous example, we set canxl_frame->flags to 0xff. Because the maximum expected length is 8, a buffer overflow of 247 bytes occurs!

Populate net_device_ops->ndo_change_mtu() to ensure that the interface's MTU can not be set to anything bigger than CAN_MTU or CANFD_MTU (depending on the device capabilities). By fixing the root cause, this prevents the buffer overflow.

Detalles técnicos trazas, registros y código del informe original
  $ ip link set can0 mtu 9999

	socket(PF_PACKET, SOCK_RAW, htons(ETH_P_CANXL));

	struct canxl_frame frame = {
		.flags = 0xff,
		.len = 2048,
	};

  1. the skb->protocol is set to ETH_P_CANXL which is valid (the
     function does not check the actual device capabilities).

  2. the length is a valid CAN XL length.

	if (can_is_canfd_skb(skb))
		return -EMSGSIZE;

	memcpy(tx_can_msg->data, cf->data, cf->len);

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.

Acceso local con privilegios de usuario (AV:L PR:L) permite escalar privilegios mediante configuración de MTU. El buffer overflow en memcpy() causa DoS o corrupción de memoria del 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

Threat Intelligence ProgramRestrict File and Directory PermissionsRemote Data StorageFilter Network TrafficExecution PreventionEncrypt Sensitive Information

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-2025-39988",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "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": "8537257874e949a59c834cecfd5a063e11b64b0b",
              "lessThan": "72de0facc50afdb101fb7197d880407f1abfc77f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8537257874e949a59c834cecfd5a063e11b64b0b",
              "lessThan": "c4e582e686c4d683c87f2b4a316385b3d81d370f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8537257874e949a59c834cecfd5a063e11b64b0b",
              "lessThan": "cbc1de71766f326a44bb798aeae4a7ef4a081cc9",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8537257874e949a59c834cecfd5a063e11b64b0b",
              "lessThan": "b26cccd87dcddc47b450a40f3b1ac3fe346efcff",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8537257874e949a59c834cecfd5a063e11b64b0b",
              "lessThan": "e587af2c89ecc6382c518febea52fa9ba81e47c0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8537257874e949a59c834cecfd5a063e11b64b0b",
              "lessThan": "38c0abad45b190a30d8284a37264d2127a6ec303",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/net/can/usb/etas_es58x/es58x_core.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.13"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.13",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.15.194",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.155",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.109",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.50",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.16.10",
              "versionType": "semver",
              "lessThanOrEqual": "6.16.*"
            },
            {
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/net/can/usb/etas_es58x/es58x_core.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-10-15T08:15:36.913",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/38c0abad45b190a30d8284a37264d2127a6ec303",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/72de0facc50afdb101fb7197d880407f1abfc77f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b26cccd87dcddc47b450a40f3b1ac3fe346efcff",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c4e582e686c4d683c87f2b4a316385b3d81d370f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cbc1de71766f326a44bb798aeae4a7ef4a081cc9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e587af2c89ecc6382c518febea52fa9ba81e47c0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: etas_es58x: populate ndo_change_mtu() to prevent buffer overflow\n\nSending an PF_PACKET allows to bypass the CAN framework logic and to\ndirectly reach the xmit() function of a CAN driver. The only check\nwhich is performed by the PF_PACKET framework is to make sure that\nskb->len fits the interface's MTU.\n\nUnfortunately, because the etas_es58x driver does not populate its\nnet_device_ops->ndo_change_mtu(), it is possible for an attacker to\nconfigure an invalid MTU by doing, for example:\n\n  $ ip link set can0 mtu 9999\n\nAfter doing so, the attacker could open a PF_PACKET socket using the\nETH_P_CANXL protocol:\n\n\tsocket(PF_PACKET, SOCK_RAW, htons(ETH_P_CANXL));\n\nto inject a malicious CAN XL frames. For example:\n\n\tstruct canxl_frame frame = {\n\t\t.flags = 0xff,\n\t\t.len = 2048,\n\t};\n\nThe CAN drivers' xmit() function are calling can_dev_dropped_skb() to\ncheck that the skb is valid, unfortunately under above conditions, the\nmalicious packet is able to go through can_dev_dropped_skb() checks:\n\n  1. the skb->protocol is set to ETH_P_CANXL which is valid (the\n     function does not check the actual device capabilities).\n\n  2. the length is a valid CAN XL length.\n\nAnd so, es58x_start_xmit() receives a CAN XL frame which it is not\nable to correctly handle and will thus misinterpret it as a CAN(FD)\nframe.\n\nThis can result in a buffer overflow. For example, using the es581.4\nvariant, the frame will be dispatched to es581_4_tx_can_msg(), go\nthrough the last check at the beginning of this function:\n\n\tif (can_is_canfd_skb(skb))\n\t\treturn -EMSGSIZE;\n\nand reach this line:\n\n\tmemcpy(tx_can_msg->data, cf->data, cf->len);\n\nHere, cf->len corresponds to the flags field of the CAN XL frame. In\nour previous example, we set canxl_frame->flags to 0xff. Because the\nmaximum expected length is 8, a buffer overflow of 247 bytes occurs!\n\nPopulate net_device_ops->ndo_change_mtu() to ensure that the\ninterface's MTU can not be set to anything bigger than CAN_MTU or\nCANFD_MTU (depending on the device capabilities). By fixing the root\ncause, this prevents the buffer overflow."
    }
  ],
  "lastModified": "2026-07-30T06:24:04.947",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}