CVE-2026-43250

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: usb: chipidea: udc: fix DMA and SG cleanup in _ep_nuke() The ChipIdea UDC driver can encounter "not page aligned sg buffer" errors when a USB device is reconnected after being disconnected during an active transfer. This occurs because _ep_nuke() returns requests to the gadget layer without properly unmapping DMA buffers or cleaning up scatter-gather bounce buffers. Root cause: When a disconnect happens during a multi-segment DMA transfer, the request's num_mapped_sgs field and sgt.sgl pointer remain set with stale values. The request is returned to the gadget driver with status -ESHUTDOWN but still has active DMA state. If the gadget driver reuses this request on reconnect without reinitializing it, the stale DMA state causes _hardware_enqueue() to skip DMA mapping (seeing non-zero num_mapped_sgs) and attempt to use freed/invalid DMA addresses, leading to alignment errors and potential memory corruption. The normal completion path via _hardware_dequeue() properly calls usb_gadget_unmap_request_by_dev() and sglist_do_debounce() before returning the request. The _ep_nuke() path must do the same cleanup to ensure requests are returned in a clean, reusable state. Fix: Add DMA unmapping and bounce buffer cleanup to _ep_nuke() to mirror the cleanup sequence in _hardware_dequeue(): - Call usb_gadget_unmap_request_by_dev() if num_mapped_sgs is set - Call sglist_do_debounce() with copy=false if bounce buffer exists This ensures that when requests are returned due to endpoint shutdown, they don't retain stale DMA mappings. The 'false' parameter to sglist_do_debounce() prevents copying data back (appropriate for shutdown path where transfer was aborted).

Severity

HIGH

CVSS score

7.8 (v3.1)

Vulnerability status

Modified

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-05-06 12:16:45.620000

Last modified

2026-10-30 13:18:49.393000

View original CVE JSON

{
  "id": "CVE-2026-43250",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-05-06T12:16:45.620",
  "lastModified": "2026-10-30T13:18:49.393",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: chipidea: udc: fix DMA and SG cleanup in _ep_nuke()\n\nThe ChipIdea UDC driver can encounter \"not page aligned sg buffer\"\nerrors when a USB device is reconnected after being disconnected\nduring an active transfer. This occurs because _ep_nuke() returns\nrequests to the gadget layer without properly unmapping DMA buffers\nor cleaning up scatter-gather bounce buffers.\n\nRoot cause:\nWhen a disconnect happens during a multi-segment DMA transfer, the\nrequest's num_mapped_sgs field and sgt.sgl pointer remain set with\nstale values. The request is returned to the gadget driver with status\n-ESHUTDOWN but still has active DMA state. If the gadget driver reuses\nthis request on reconnect without reinitializing it, the stale DMA\nstate causes _hardware_enqueue() to skip DMA mapping (seeing non-zero\nnum_mapped_sgs) and attempt to use freed/invalid DMA addresses,\nleading to alignment errors and potential memory corruption.\n\nThe normal completion path via _hardware_dequeue() properly calls\nusb_gadget_unmap_request_by_dev() and sglist_do_debounce() before\nreturning the request. The _ep_nuke() path must do the same cleanup\nto ensure requests are returned in a clean, reusable state.\n\nFix:\nAdd DMA unmapping and bounce buffer cleanup to _ep_nuke() to mirror\nthe cleanup sequence in _hardware_dequeue():\n- Call usb_gadget_unmap_request_by_dev() if num_mapped_sgs is set\n- Call sglist_do_debounce() with copy=false if bounce buffer exists\n\nThis ensures that when requests are returned due to endpoint shutdown,\nthey don't retain stale DMA mappings. The 'false' parameter to\nsglist_do_debounce() prevents copying data back (appropriate for\nshutdown path where transfer was aborted)."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "drivers/usb/chipidea/udc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "aa69a8093ff985873cb44fe1157bd6db29a20fe4",
              "lessThan": "1497998749600411d75e60a44f7e572b2348bd9a",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "aa69a8093ff985873cb44fe1157bd6db29a20fe4",
              "lessThan": "aad97c92119cb85db105ddda4a44c86cc0748e8c",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "aa69a8093ff985873cb44fe1157bd6db29a20fe4",
              "lessThan": "1b72b834511d17f4d069d512f78671f3f210a2f1",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "aa69a8093ff985873cb44fe1157bd6db29a20fe4",
              "lessThan": "f4fbf2d4750d12ac8525d2efac1016fa0d84d4ec",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "aa69a8093ff985873cb44fe1157bd6db29a20fe4",
              "lessThan": "e74c436f8568af1c60942469d0a2300b3ada3857",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "aa69a8093ff985873cb44fe1157bd6db29a20fe4",
              "lessThan": "cea2a1257a3b5ea3e769a445b34af13e6aa5a123",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "drivers/usb/chipidea/udc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "2.6.29",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "2.6.29",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.191",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.160",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.75",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.16",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.19.6",
              "lessThanOrEqual": "6.19.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.0",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "2.6.29",
              "versionEndExcluding": "6.12.75",
              "matchCriteriaId": "3C0B1026-23F7-4F83-B19F-153326AAEC72"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "6.13",
              "versionEndExcluding": "6.18.16",
              "matchCriteriaId": "B4B8CDA9-BADF-4CF5-8B3B-702DE8EEA40B"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "6.19",
              "versionEndExcluding": "6.19.6",
              "matchCriteriaId": "373EEEDA-FAA1-4FB4-B6ED-DB4DD99DBE67"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1497998749600411d75e60a44f7e572b2348bd9a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1b72b834511d17f4d069d512f78671f3f210a2f1",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/aad97c92119cb85db105ddda4a44c86cc0748e8c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cea2a1257a3b5ea3e769a445b34af13e6aa5a123",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/e74c436f8568af1c60942469d0a2300b3ada3857",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/f4fbf2d4750d12ac8525d2efac1016fa0d84d4ec",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    }
  ]
}