FKIE_CVE-2026-46123

Vulnerability from fkie_nvd - Published: 2026-05-28 10:16 - Updated: 2026-06-24 16:51
Severity ?
7.7 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: virtio_bt: clamp rx length before skb_put virtbt_rx_work() calls skb_put(skb, len) where len comes directly from virtqueue_get_buf() with no validation against the buffer we posted to the device. The RX skb is allocated in virtbt_add_inbuf() and exposed to virtio as exactly 1000 bytes via sg_init_one(). Checking len against skb_tailroom(skb) is not sufficient because alloc_skb() can leave more tailroom than the 1000 bytes actually handed to the device. A malicious or buggy backend can therefore report used.len between 1001 and skb_tailroom(skb), causing skb_put() to include uninitialized kernel heap bytes that were never written by the device. The same path also accepts len == 0, in which case skb_put(skb, 0) leaves the skb empty but virtbt_rx_handle() still reads the pkt_type byte from skb->data, consuming uninitialized memory. Define VIRTBT_RX_BUF_SIZE once and reuse it in alloc_skb() and sg_init_one(), and gate virtbt_rx_work() on that same constant so the bound checked matches the buffer actually exposed to the device. Reject used.len == 0 in the same gate so an empty completion can no longer reach virtbt_rx_handle(). Use bt_dev_err_ratelimited() because the length value comes from an untrusted backend that can otherwise flood the kernel log. Same class of bug as commit c04db81cd028 ("net/9p: Fix buffer overflow in USB transport layer"), which hardened the USB 9p transport against unchecked device-reported length.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/21bd244b6de5d2fe1063c23acc93fbdd2b20d112Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4236e55b2d9d1ffd3b4bdf8ebbb86e5a0a526b4aPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6c1730099a6fc18b183bd6c1adad3b54adcaeda9Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b40cdd1b1370d76e9e760af4490cb4a351cceeadPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e6b4296f170d949ebba937cf6a3f247ec9550d2cPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ed41c81d30b211a671667259c3b5feeba0e062d5Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fd91fa2678ab603dfb285416c1cf3843d7be1e41Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 6.1
linux linux_kernel 6.1
linux linux_kernel 6.1
linux linux_kernel 6.1
linux linux_kernel 6.1
linux linux_kernel 6.1
linux linux_kernel 7.1
linux linux_kernel 7.1
To clipboard 

{
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              "status": "unaffected",
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              "status": "unaffected",
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              "lessThanOrEqual": "6.18.*",
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              "lessThanOrEqual": "7.0.*",
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              "versionType": "original_commit_for_fix"
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          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
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          "negate": false,
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: virtio_bt: clamp rx length before skb_put\n\nvirtbt_rx_work() calls skb_put(skb, len) where len comes directly\nfrom virtqueue_get_buf() with no validation against the buffer we\nposted to the device. The RX skb is allocated in virtbt_add_inbuf()\nand exposed to virtio as exactly 1000 bytes via sg_init_one().\n\nChecking len against skb_tailroom(skb) is not sufficient because\nalloc_skb() can leave more tailroom than the 1000 bytes actually\nhanded to the device. A malicious or buggy backend can therefore\nreport used.len between 1001 and skb_tailroom(skb), causing skb_put()\nto include uninitialized kernel heap bytes that were never written by\nthe device.\n\nThe same path also accepts len == 0, in which case skb_put(skb, 0)\nleaves the skb empty but virtbt_rx_handle() still reads the pkt_type\nbyte from skb-\u003edata, consuming uninitialized memory.\n\nDefine VIRTBT_RX_BUF_SIZE once and reuse it in alloc_skb() and\nsg_init_one(), and gate virtbt_rx_work() on that same constant so\nthe bound checked matches the buffer actually exposed to the device.\nReject used.len == 0 in the same gate so an empty completion can\nno longer reach virtbt_rx_handle().\n\nUse bt_dev_err_ratelimited() because the length value comes from an\nuntrusted backend that can otherwise flood the kernel log.\n\nSame class of bug as commit c04db81cd028 (\"net/9p: Fix buffer\noverflow in USB transport layer\"), which hardened the USB 9p\ntransport against unchecked device-reported length."
    }
  ],
  "id": "CVE-2026-46123",
  "lastModified": "2026-06-24T16:51:21.783",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.7,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.5,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-05-28T10:16:27.810",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/21bd244b6de5d2fe1063c23acc93fbdd2b20d112"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/4236e55b2d9d1ffd3b4bdf8ebbb86e5a0a526b4a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/6c1730099a6fc18b183bd6c1adad3b54adcaeda9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/b40cdd1b1370d76e9e760af4490cb4a351cceead"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/e6b4296f170d949ebba937cf6a3f247ec9550d2c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/ed41c81d30b211a671667259c3b5feeba0e062d5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/fd91fa2678ab603dfb285416c1cf3843d7be1e41"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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