CVE-2026-46123 (GCVE-0-2026-46123)
Vulnerability from cvelistv5
Published
2026-05-28 09:35
Modified
2026-08-05 12:29
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
Impacted products
Vendor Product Version
Linux Linux Version: cf2719a21fdb9d4c8e9c834d279163609bef575d
Version: 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be
Version: 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be
Version: 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be
Version: 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be
Version: 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be
Version: 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be
Version: 9b67438e315b925a699f0178f4a48baf3d2d6ef4
Version: 5.15.78   ≤
Version: 6.0.8   ≤
Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/bluetooth/virtio_bt.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4236e55b2d9d1ffd3b4bdf8ebbb86e5a0a526b4a",
              "status": "affected",
              "version": "cf2719a21fdb9d4c8e9c834d279163609bef575d",
              "versionType": "git"
            },
            {
              "lessThan": "fd91fa2678ab603dfb285416c1cf3843d7be1e41",
              "status": "affected",
              "version": "160fbcf3bfb93c3c086427f9f4c8bc70f217e9be",
              "versionType": "git"
            },
            {
              "lessThan": "ed41c81d30b211a671667259c3b5feeba0e062d5",
              "status": "affected",
              "version": "160fbcf3bfb93c3c086427f9f4c8bc70f217e9be",
              "versionType": "git"
            },
            {
              "lessThan": "6c1730099a6fc18b183bd6c1adad3b54adcaeda9",
              "status": "affected",
              "version": "160fbcf3bfb93c3c086427f9f4c8bc70f217e9be",
              "versionType": "git"
            },
            {
              "lessThan": "b40cdd1b1370d76e9e760af4490cb4a351cceead",
              "status": "affected",
              "version": "160fbcf3bfb93c3c086427f9f4c8bc70f217e9be",
              "versionType": "git"
            },
            {
              "lessThan": "e6b4296f170d949ebba937cf6a3f247ec9550d2c",
              "status": "affected",
              "version": "160fbcf3bfb93c3c086427f9f4c8bc70f217e9be",
              "versionType": "git"
            },
            {
              "lessThan": "21bd244b6de5d2fe1063c23acc93fbdd2b20d112",
              "status": "affected",
              "version": "160fbcf3bfb93c3c086427f9f4c8bc70f217e9be",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9b67438e315b925a699f0178f4a48baf3d2d6ef4",
              "versionType": "git"
            },
            {
              "lessThan": "5.15.209",
              "status": "affected",
              "version": "5.15.78",
              "versionType": "semver"
            },
            {
              "lessThan": "6.1",
              "status": "affected",
              "version": "6.0.8",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/bluetooth/virtio_bt.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.1"
            },
            {
              "lessThan": "6.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.209",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.140",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.88",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.30",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.209",
                  "versionStartIncluding": "5.15.78",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.175",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.140",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.88",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.30",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.7",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.0.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The malicious value is the virtqueue used-buffer length supplied by the local virtio backend (host VMM / device-emulation process), reached over the virtio bus rather than the network stack or physical contact; virtio_bt exists only as a paravirtualized transport inside VM guests.\nAC:L - The backend fully and deterministically controls the reported `len`; choosing a value above tailroom reliably panics the guest and a value in (1000, tailroom] reliably exposes uninitialized heap, with no uncontrolled conditions.\nPR:N - The attacking device backend authenticates nothing and holds no privileges within the victim guest kernel, exactly as malicious-peripheral (USB) device bugs are scored PR:N in this tree.\nUI:N - The backend autonomously posts a crafted RX completion as soon as the device is opened; no guest-side user action is required.\nS:U - Both the vulnerable component and the impacted resources (guest kernel heap disclosure and guest kernel panic) reside within the guest kernel\u0027s security authority, so no scope boundary is crossed by the impact.\nC:H - An oversized `len` causes ~700 bytes of uninitialized kernel heap to be injected into the HCI receive path (observable via HCI monitor/raw sockets); this is an unbounded info leak, well beyond a few bytes.\nI:N - The bug only advances skb length/tail pointers and never grants an out-of-bounds write, UAF, or other primitive to modify kernel data beyond what a device can already do legitimately.\nA:H - A `len` exceeding skb tailroom drives `skb_put()` into `skb_over_panic()` \u2192 `BUG()`, giving the backend a reliable, repeatable guest kernel panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:29:52.762Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4236e55b2d9d1ffd3b4bdf8ebbb86e5a0a526b4a"
        },
        {
          "url": "https://git.kernel.org/stable/c/fd91fa2678ab603dfb285416c1cf3843d7be1e41"
        },
        {
          "url": "https://git.kernel.org/stable/c/ed41c81d30b211a671667259c3b5feeba0e062d5"
        },
        {
          "url": "https://git.kernel.org/stable/c/6c1730099a6fc18b183bd6c1adad3b54adcaeda9"
        },
        {
          "url": "https://git.kernel.org/stable/c/b40cdd1b1370d76e9e760af4490cb4a351cceead"
        },
        {
          "url": "https://git.kernel.org/stable/c/e6b4296f170d949ebba937cf6a3f247ec9550d2c"
        },
        {
          "url": "https://git.kernel.org/stable/c/21bd244b6de5d2fe1063c23acc93fbdd2b20d112"
        }
      ],
      "title": "Bluetooth: virtio_bt: clamp rx length before skb_put",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46123",
    "datePublished": "2026-05-28T09:35:38.003Z",
    "dateReserved": "2026-05-13T15:03:33.098Z",
    "dateUpdated": "2026-08-05T12:29:52.762Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.