{
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        "name": "Kernel"
      },
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  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43327.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nUSB: dummy-hcd: Fix locking/synchronization error\n\nSyzbot testing was able to provoke an addressing exception and crash\nin the usb_gadget_udc_reset() routine in\ndrivers/usb/gadgets/udc/core.c, resulting from the fact that the\nroutine was called with a second (\"driver\") argument of NULL.  The bad\ncaller was set_link_state() in dummy_hcd.c, and the problem arose\nbecause of a race between a USB reset and driver unbind.\n\nThese sorts of races were not supposed to be possible; commit\n7dbd8f4cabd9 (\"USB: dummy-hcd: Fix erroneous synchronization change\"),\nalong with a few followup commits, was written specifically to prevent\nthem.  As it turns out, there are (at least) two errors remaining in\nthe code.  Another patch will address the second error; this one is\nconcerned with the first.\n\nThe error responsible for the syzbot crash occurred because the\nstop_activity() routine will sometimes drop and then re-acquire the\ndum-\u003elock spinlock.  A call to stop_activity() occurs in\nset_link_state() when handling an emulated USB reset, after the test\nof dum-\u003eints_enabled and before the increment of dum-\u003ecallback_usage.\nThis allowed another thread (doing a driver unbind) to sneak in and\ngrab the spinlock, and then clear dum-\u003eints_enabled and dum-\u003edriver.\nNormally this other thread would have to wait for dum-\u003ecallback_usage\nto go down to 0 before it would clear dum-\u003edriver, but in this case it\ndidn't have to wait since dum-\u003ecallback_usage had not yet been\nincremented.\n\nThe fix is to increment dum-\u003ecallback_usage _before_ calling\nstop_activity() instead of after.  Then the thread doing the unbind\nwill not clear dum-\u003edriver until after the call to\nusb_gadget_udc_reset() safely returns and dum-\u003ecallback_usage has been\ndecremented again.",
  "id": "CVE-2026-43327",
  "modified": "2026-07-15T01:49:06.807289106Z",
  "published": "2026-05-08T13:31:12.896Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/218886b2ef2dea7627d3700ab0abaf4bf9d1161f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/616a63ff495df12863692ab3f9f7b84e3fa7a66d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6350c7dd33ab481ef41c931a238361490c32d15c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/69ab97a693251d6a6093e630060a3c744fd58524"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/791966f85b439b261bf19865cf1c07c065ffb4b4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/805b1833d6ed6da5086e610578a28e71bb54fbbb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cc97fb5969177cccce2e23b31298df220fc7570d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/efbd9441f1e769a7aae1813d497cec09cbdff031"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43327.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43327"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "summary": "USB: dummy-hcd: Fix locking/synchronization error"
}