{"cve":"CVE-2026-43250","nvd":{"published":"2026-05-06T12:16:45.620","modified":"2026-10-21T13:18:53.280","status":"Modified","description":"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).","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-787"],"references":["https://git.kernel.org/stable/c/1b72b834511d17f4d069d512f78671f3f210a2f1","https://git.kernel.org/stable/c/aad97c92119cb85db105ddda4a44c86cc0748e8c","https://git.kernel.org/stable/c/cea2a1257a3b5ea3e769a445b34af13e6aa5a123","https://git.kernel.org/stable/c/e74c436f8568af1c60942469d0a2300b3ada3857","https://git.kernel.org/stable/c/f4fbf2d4750d12ac8525d2efac1016fa0d84d4ec"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-43250","score":0.00163,"percentile":0.05479,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}