CVE-2026-64586: Software Security Vulnerability Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5rg4-8h2h-x94w",
  "modified" : "2026-08-23T15:32:55Z",
  "published" : "2026-08-06T09:30:32Z",
  "aliases" : [ "CVE-2026-64586" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: brcmfmac: drain bus_reset work on device removal\n\nbrcmf_fw_crashed() and the debugfs \"reset\" entry both schedule\ndrvr->bus_reset, whose callback recovers drvr through container_of()\nand dereferences it.  The removal path frees drvr (brcmf_free ->\nwiphy_free) without draining the work, so a bus_reset callback pending\nor running during removal can outlive drvr.\n\nCancellation cannot live in brcmf_detach() or brcmf_free(): the work\ncallback reaches teardown through the bus .reset op (PCIe\nbrcmf_pcie_reset -> brcmf_detach; SDIO brcmf_sdio_bus_reset ->\nbrcmf_sdiod_remove -> brcmf_free), so cancelling there would wait for\nthe running work and deadlock.\n\nAdd a per-bus mutex (bus_reset_lock) and route all arming through\nbrcmf_bus_schedule_reset(), which under the lock skips when the bus is\nmarked removing.  Each bus remove entry calls\nbrcmf_bus_cancel_reset_work(), which under the same lock sets removing\nand cancels the work.  Holding the mutex across cancel_work_sync() makes\nthe set-removing + drain step atomic.  Every producer reaches the arming\npath from process context -- the PCIe firmware-halt notification runs in\nthe threaded IRQ handler (brcmf_pcie_isr_thread) and the SDIO hostmail\npath runs from the data workqueue -- so the mutex is taken only in\nsleepable contexts.  Where applicable the remove entry first stops the\nfirmware-crash producer: on PCIe mask the mailbox and synchronize_irq;\non SDIO unregister the bus interrupt and cancel the data worker, which\nalso reports firmware halts through brcmf_fw_crashed().  The mutex is\ninitialized at bus allocation.  The SDIO suspend power-off path frees\ndrvr through the same brcmf_sdiod_remove() and takes the same lock;\nresume re-allows the work only on a successful re-probe.\n\nAlso guard brcmf_fw_crashed() against a NULL bus_if/drvr: it can fire\nbefore brcmf_attach() wires up drvr, and it dereferences drvr\n(bphy_err/brcmf_dev_coredump) before reaching the arming gate.\n\nThe bus_reset work is shared across buses, so the drain is applied to\nevery remove path: PCIe (the .reset op introduced by the Fixes commit),\nSDIO (arms the same work through brcmf_fw_crashed()), and USB (via the\ndebugfs \"reset\" entry).  cancel_work_sync() drains a running or pending\nbus_reset work item before removal frees drvr, and patch 1/2 makes the\nscratch-buffer release safe when reset teardown has already released\nthose DMA buffers.\n\nThis patch fixes the lifetime of the bus_reset work item itself.  It does\nnot attempt to address the separate, pre-existing lifetime of the\nasynchronous firmware completion started by the PCIe reset path.  That\ncallback needs its own lifetime/ownership protocol and is being tracked\nseparately.\n\nThis issue was found by an in-house static analysis tool.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-64586"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/02d378828af8bb74f6c2f4d2bee3c77cf16c861e"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/177a25be1195f8bdc6160ba5f1a5699f7041c985"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/43b25879f004c98defa2776bedc6ca4763c51945"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/4824e3bcc68f8d678b409039d1bb48c7b5ea73dc"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/61127dd20920bf28460a1609aabb0dafa2f54fac"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/9dfb09cb0abbf92a06f93e0715e163aa188a84da"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/c268331845ee00dbdbccb000826bb612dff2bee7"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/e3815d1ffbb9be4f1605ddc3b427557893461683"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-416" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-06T08:16:33Z"
  }
}