FKIE_CVE-2026-98025

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 11:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: net: usb: cx82310_eth: drop URB after 0xffff reboot sentinel to prevent partial_data heap overflow The 0xffff length sentinel detects a router reboot and schedules re-enabling of ethernet mode, but then falls through to the rest of the loop body. The next check is } else if (len > CX82310_MTU) { which is the else of the just-matched if -- it never fires for len == 0xffff. The MTU bound that normally caps the incomplete-packet save path is silently bypassed. With 0xffff > skb->len always true (rx_urb_size is 4096), the incomplete-packet branch saves dev->partial_len = skb->len bytes into dev->partial_data. partial_data is kmalloc(hard_mtu) = kmalloc(CX82310_MTU + 2) = 1516 bytes, but skb->len after the 2-byte header pull can be up to 4094. A device that sends a 4096-byte URB starting with [0xff 0xff] therefore copies 4094 device-provided bytes into a buffer allocated for 1516 bytes, exceeding its requested size by 2578 bytes. The next URB then reads dev->partial_len (4094) back from the same 1516-byte buffer and dev->partial_rem (65535 - 4094 = 61441) from the new URB's ~4KB skb, both well past their allocations, and delivers the spliced result as a 64KB "frame" to the network stack. Bail out of rx_fixup after scheduling the re-enable work; the remainder of a reboot-marker URB is not meaningful packet data. This restores the invariant that partial_len < CX82310_MTU + 2 on the save path, since every other route there has already passed the MTU check.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/237c9ae7145772af147e4665f158938350fa5658
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3bd689409bb1c93bdc6dd8ec6cbf5161bc4f0287
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5d50e90add8b4a978395e893e81954d19d58a7c5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/659654654eb140851467af41d610473c100c7975
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/usb/cx82310_eth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3bd689409bb1c93bdc6dd8ec6cbf5161bc4f0287",
              "status": "affected",
              "version": "ca139d76b0d9e59d18f2d2ec8f0d81b82acd6808",
              "versionType": "git"
            },
            {
              "lessThan": "659654654eb140851467af41d610473c100c7975",
              "status": "affected",
              "version": "ca139d76b0d9e59d18f2d2ec8f0d81b82acd6808",
              "versionType": "git"
            },
            {
              "lessThan": "237c9ae7145772af147e4665f158938350fa5658",
              "status": "affected",
              "version": "ca139d76b0d9e59d18f2d2ec8f0d81b82acd6808",
              "versionType": "git"
            },
            {
              "lessThan": "5d50e90add8b4a978395e893e81954d19d58a7c5",
              "status": "affected",
              "version": "ca139d76b0d9e59d18f2d2ec8f0d81b82acd6808",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5adf7fbdfa3e9e425b04771e1d64c4e184ad8fdb",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c1b187a86a176e42f5e48066556980e3232b6cab",
              "versionType": "git"
            },
            {
              "lessThan": "4.20",
              "status": "affected",
              "version": "4.19.322",
              "versionType": "semver"
            },
            {
              "lessThan": "5.5",
              "status": "affected",
              "version": "5.4.284",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/usb/cx82310_eth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.10"
            },
            {
              "lessThan": "5.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "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: usb: cx82310_eth: drop URB after 0xffff reboot sentinel to prevent partial_data heap overflow\n\nThe 0xffff length sentinel detects a router reboot and schedules\nre-enabling of ethernet mode, but then falls through to the rest\nof the loop body.  The next check is\n\n\t} else if (len \u003e CX82310_MTU) {\n\nwhich is the else of the just-matched if -- it never fires for\nlen == 0xffff.  The MTU bound that normally caps the\nincomplete-packet save path is silently bypassed.\n\nWith 0xffff \u003e skb-\u003elen always true (rx_urb_size is 4096), the\nincomplete-packet branch saves dev-\u003epartial_len = skb-\u003elen bytes\ninto dev-\u003epartial_data.  partial_data is kmalloc(hard_mtu) =\nkmalloc(CX82310_MTU + 2) = 1516 bytes, but skb-\u003elen after the\n2-byte header pull can be up to 4094.  A device that sends a\n4096-byte URB starting with [0xff 0xff] therefore copies 4094\ndevice-provided bytes into a buffer allocated for 1516 bytes,\nexceeding its requested size by 2578 bytes.\n\nThe next URB then reads dev-\u003epartial_len (4094) back from the same\n1516-byte buffer and dev-\u003epartial_rem (65535 - 4094 = 61441) from\nthe new URB\u0027s ~4KB skb, both well past their allocations, and\ndelivers the spliced result as a 64KB \"frame\" to the network\nstack.\n\nBail out of rx_fixup after scheduling the re-enable work; the\nremainder of a reboot-marker URB is not meaningful packet data.\nThis restores the invariant that partial_len \u003c CX82310_MTU + 2 on\nthe save path, since every other route there has already passed\nthe MTU check."
    }
  ],
  "id": "CVE-2026-98025",
  "lastModified": "2026-09-25T11:17:31.110",
  "metrics": {},
  "published": "2026-09-25T11:17:31.110",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/237c9ae7145772af147e4665f158938350fa5658"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3bd689409bb1c93bdc6dd8ec6cbf5161bc4f0287"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5d50e90add8b4a978395e893e81954d19d58a7c5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/659654654eb140851467af41d610473c100c7975"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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