{"id":"CVE-2026-64586","title":"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 thr…","summary":"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 thr…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","published":"2026-08-06","updated":"2026-08-08","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-64586","references":[{"url":"https://git.kernel.org/stable/c/177a25be1195f8bdc6160ba5f1a5699f7041c985","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/43b25879f004c98defa2776bedc6ca4763c51945","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9dfb09cb0abbf92a06f93e0715e163aa188a84da"},{"url":"https://git.kernel.org/stable/c/4824e3bcc68f8d678b409039d1bb48c7b5ea73dc"},{"url":"https://git.kernel.org/stable/c/61127dd20920bf28460a1609aabb0dafa2f54fac"},{"url":"https://git.kernel.org/stable/c/c268331845ee00dbdbccb000826bb612dff2bee7"},{"url":"https://git.kernel.org/stable/c/e3815d1ffbb9be4f1605ddc3b427557893461683"},{"url":"https://git.kernel.org/stable/c/02d378828af8bb74f6c2f4d2bee3c77cf16c861e"}],"tags":["nvd","cve.org"],"epss":0.0025,"epssPercentile":0.163,"ingestedAt":"2026-08-08T21:30:13.185Z","vendor":"Linux","product":"Linux","affected":["Linux >= 4684997d9eea29380000e062755aa6d368d789a3 < 9dfb09cb0abbf92a06f93e0715e163aa188a84da","Linux >= 4684997d9eea29380000e062755aa6d368d789a3 < 4824e3bcc68f8d678b409039d1bb48c7b5ea73dc","Linux >= 4684997d9eea29380000e062755aa6d368d789a3 < 61127dd20920bf28460a1609aabb0dafa2f54fac","Linux >= 4684997d9eea29380000e062755aa6d368d789a3 < c268331845ee00dbdbccb000826bb612dff2bee7","Linux >= 4684997d9eea29380000e062755aa6d368d789a3 < e3815d1ffbb9be4f1605ddc3b427557893461683","Linux >= 4684997d9eea29380000e062755aa6d368d789a3 < 02d378828af8bb74f6c2f4d2bee3c77cf16c861e","Linux >= 4684997d9eea29380000e062755aa6d368d789a3 < 177a25be1195f8bdc6160ba5f1a5699f7041c985","Linux >= 4684997d9eea29380000e062755aa6d368d789a3 < 43b25879f004c98defa2776bedc6ca4763c51945","Linux 5.2"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:43:21.576355Z"},"slug":"CVE-2026-64586","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}