CVE-2026-64586 (GCVE-0-2026-64586)
Vulnerability from cvelistv5
Published
2026-08-06 07:06
Modified
2026-08-23 12:45
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: drain bus_reset work on device removal
brcmf_fw_crashed() and the debugfs "reset" entry both schedule
drvr->bus_reset, whose callback recovers drvr through container_of()
and dereferences it. The removal path frees drvr (brcmf_free ->
wiphy_free) without draining the work, so a bus_reset callback pending
or running during removal can outlive drvr.
Cancellation cannot live in brcmf_detach() or brcmf_free(): the work
callback reaches teardown through the bus .reset op (PCIe
brcmf_pcie_reset -> brcmf_detach; SDIO brcmf_sdio_bus_reset ->
brcmf_sdiod_remove -> brcmf_free), so cancelling there would wait for
the running work and deadlock.
Add a per-bus mutex (bus_reset_lock) and route all arming through
brcmf_bus_schedule_reset(), which under the lock skips when the bus is
marked removing. Each bus remove entry calls
brcmf_bus_cancel_reset_work(), which under the same lock sets removing
and cancels the work. Holding the mutex across cancel_work_sync() makes
the set-removing + drain step atomic. Every producer reaches the arming
path from process context -- the PCIe firmware-halt notification runs in
the threaded IRQ handler (brcmf_pcie_isr_thread) and the SDIO hostmail
path runs from the data workqueue -- so the mutex is taken only in
sleepable contexts. Where applicable the remove entry first stops the
firmware-crash producer: on PCIe mask the mailbox and synchronize_irq;
on SDIO unregister the bus interrupt and cancel the data worker, which
also reports firmware halts through brcmf_fw_crashed(). The mutex is
initialized at bus allocation. The SDIO suspend power-off path frees
drvr through the same brcmf_sdiod_remove() and takes the same lock;
resume re-allows the work only on a successful re-probe.
Also guard brcmf_fw_crashed() against a NULL bus_if/drvr: it can fire
before brcmf_attach() wires up drvr, and it dereferences drvr
(bphy_err/brcmf_dev_coredump) before reaching the arming gate.
The bus_reset work is shared across buses, so the drain is applied to
every remove path: PCIe (the .reset op introduced by the Fixes commit),
SDIO (arms the same work through brcmf_fw_crashed()), and USB (via the
debugfs "reset" entry). cancel_work_sync() drains a running or pending
bus_reset work item before removal frees drvr, and patch 1/2 makes the
scratch-buffer release safe when reset teardown has already released
those DMA buffers.
This patch fixes the lifetime of the bus_reset work item itself. It does
not attempt to address the separate, pre-existing lifetime of the
asynchronous firmware completion started by the PCIe reset path. That
callback needs its own lifetime/ownership protocol and is being tracked
separately.
This issue was found by an in-house static analysis tool.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 4684997d9eea29380000e062755aa6d368d789a3 Version: 4684997d9eea29380000e062755aa6d368d789a3 Version: 4684997d9eea29380000e062755aa6d368d789a3 Version: 4684997d9eea29380000e062755aa6d368d789a3 Version: 4684997d9eea29380000e062755aa6d368d789a3 Version: 4684997d9eea29380000e062755aa6d368d789a3 Version: 4684997d9eea29380000e062755aa6d368d789a3 Version: 4684997d9eea29380000e062755aa6d368d789a3 |
||
{
"containers": {
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{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/bus.h",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.h",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "4684997d9eea29380000e062755aa6d368d789a3",
"versionType": "git"
},
{
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"status": "affected",
"version": "4684997d9eea29380000e062755aa6d368d789a3",
"versionType": "git"
},
{
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"status": "affected",
"version": "4684997d9eea29380000e062755aa6d368d789a3",
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{
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"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
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}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/bus.h",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.h",
"drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.2"
},
{
"lessThan": "5.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.266",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.217",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.184",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.151",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.103",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.44",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.2",
"vulnerable": true
},
{
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{
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{
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],
"negate": false,
"operator": "OR"
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],
"descriptions": [
{
"lang": "en",
"value": "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-\u003ebus_reset, whose callback recovers drvr through container_of()\nand dereferences it. The removal path frees drvr (brcmf_free -\u003e\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 -\u003e brcmf_detach; SDIO brcmf_sdio_bus_reset -\u003e\nbrcmf_sdiod_remove -\u003e 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."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:A - bus_reset is armed by brcmf_fw_crashed() when Broadcom fullmac signals FWHALT (PCIe mailbox ISR thread / SDIO hostmail). An adjacent 802.11 attacker can induce that halt with malformed frames; the pending work then races device removal (USB hot-unplug, SDIO suspend power-off) that frees drvr without draining the work.\nAC:L - The attacker repeatedly induces firmware halts to schedule bus_reset and can align removal (USB unplug on shared dongles/kiosks, or SDIO suspend) so the work runs after wiphy_free; both sides are attacker-influenced and freely retryable, so success does not depend on uncontrollable timing.\nPR:N - FWHALT delivery and brcmf_fw_crashed() need no host credentials; concurrent free via USB disconnect or automatic SDIO power-cut suspend likewise requires no account or capability. The debugfs reset path is root-only but is not the highest-severity reachability.\nUI:N - Firmware-halt recovery and device removal/suspend paths run in kernel workqueues and bus callbacks without the victim opening a file, mounting media, or otherwise interacting.\nS:U - The UAF corrupts host-kernel heap (struct brcmf_pub embedded in the wiphy) within the same kernel security authority; it is not a VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - Use-after-free of drvr via container_of on the freed bus_reset work_struct lets an attacker reallocate the wiphy/drvr slab and observe attacker-controlled object contents through subsequent driver dereferences, yielding an arbitrary kernel read primitive.\nI:H - The recycled work_struct/drvr is dispatched by the workqueue (func pointer / bus_if ops), enabling heap corruption and control-flow hijack when brcmf_core_bus_reset runs on attacker-shaped memory after brcmf_free/wiphy_free.\nA:H - Even without full exploitation, running bus_reset after wiphy_free dereferences freed drvr/bus_if state and reliably causes kernel oops/panic or driver teardown failure, denying availability of the host."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-23T12:45:44.685Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"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"
},
{
"url": "https://git.kernel.org/stable/c/177a25be1195f8bdc6160ba5f1a5699f7041c985"
},
{
"url": "https://git.kernel.org/stable/c/43b25879f004c98defa2776bedc6ca4763c51945"
}
],
"title": "wifi: brcmfmac: drain bus_reset work on device removal",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64586",
"datePublished": "2026-08-06T07:06:27.158Z",
"dateReserved": "2026-07-19T15:36:31.798Z",
"dateUpdated": "2026-08-23T12:45:44.685Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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