FKIE_CVE-2026-43250

Vulnerability from fkie_nvd - Published: 2026-05-06 12:16 - Updated: 2026-05-12 18:51
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
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).
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1b72b834511d17f4d069d512f78671f3f210a2f1Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cea2a1257a3b5ea3e769a445b34af13e6aa5a123Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e74c436f8568af1c60942469d0a2300b3ada3857Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f4fbf2d4750d12ac8525d2efac1016fa0d84d4ecPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
To clipboard 

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      "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\u0027s 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\u0027t retain stale DMA mappings. The \u0027false\u0027 parameter to\nsglist_do_debounce() prevents copying data back (appropriate for\nshutdown path where transfer was aborted)."
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  "id": "CVE-2026-43250",
  "lastModified": "2026-05-12T18:51:16.140",
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          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
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          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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