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CVE Record

CVE-2024-35811: wifi: brcmfmac: Fix use-after-free bug in brcmf_cfg80211_detach

In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: Fix use-after-free bug in brcmf_cfg80211_detach This is the candidate patch of CVE-2023-47233 : https://nvd.nist.gov/vuln/detail/CVE-2023-47233 In brcm80211 driver,it starts with the following invoking chain to start init a timeout worker: ->brcmf_usb_probe ->brcmf_usb_probe_cb ->brcmf_attach ->brcmf_bus_started ->brcmf_cfg80211_attach ->wl_init_priv ->brcmf_init_escan ->INIT_WORK(&cfg->escan_timeout_work, brcmf_cfg80211_escan_timeout_worker); If we disconnect the USB by hotplug, it will call brcmf_usb_disconnect to make cleanup. The invoking chain is : brcmf_usb_disconnect ->brcmf_usb_disconnect_cb ->brcmf_detach ->brcmf_cfg80211_detach ->kfree(cfg); While the timeout woker may still be running. This will cause a use-after-free bug on cfg in brcmf_cfg80211_escan_timeout_worker. Fix it by deleting the timer and canceling the worker in brcmf_cfg80211_detach. [arend.vanspriel@broadcom.com: keep timer delete as is and cancel work just before free]

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux Broadcom Wi-Fi driver can access memory after releasing it when a USB adapter is disconnected while a scan-timeout task remains active. This may crash or corrupt an affected system. The CVSS score is 8.8, but the supplied sources do not establish real-world exploitation.

Executive priority

Prioritize affected endpoints, appliances, and embedded systems where Broadcom USB Wi-Fi is present or untrusted users can access hardware. Treat remediation as high priority, while avoiding emergency claims unsupported by exploitation evidence. Confirm exposure before broad operational disruption because the vulnerable driver and hardware combination narrows the affected population.

Technical view

The brcmfmac cleanup path frees its cfg structure without first ensuring escan_timeout_work has stopped. A concurrent timeout worker can subsequently dereference the freed object. The kernel fix deletes the timer and cancels the worker immediately before freeing cfg. The disclosed trigger involves USB hot-unplug during pending asynchronous work.

Likely exposure

Exposure is limited to Linux systems using affected kernels with the brcmfmac Broadcom FullMAC Wi-Fi driver and relevant USB hardware. Systems without that driver or hardware are unlikely to be exposed. The supplied version data is irregular, so determine status using the running distribution's advisory and backport information.

Exploitation context

The supplied CVSS vector rates this as adjacent, low-complexity, unauthenticated, and requiring no user interaction, with potentially high confidentiality, integrity, and availability impact. However, the described trigger requires a USB disconnect timing condition. CISA KEV status is false, and no supplied source reports active exploitation or a public exploit.

Researcher notes

This is a teardown-versus-worker race in brcmf_cfg80211_detach: cfg is freed while escan_timeout_work may execute. The source describes canceling work immediately before free while retaining timer deletion. It calls this a candidate patch related to CVE-2023-47233; that relationship should not be treated as proof that affected-version or exploitation findings are identical.

Mitigation direction

  • Install a vendor-supported kernel containing the applicable stable fix or distribution backport.
  • Reboot into the updated kernel; installing packages alone may leave the vulnerable kernel running.
  • If patching is delayed, follow vendor guidance and limit untrusted access to relevant USB Wi-Fi hardware.
  • Do not infer safety from version numbers alone; confirm distribution-specific backport status.

Validation and detection

  • Inventory systems using the brcmfmac driver and Broadcom USB Wi-Fi hardware.
  • Record each system's running kernel version, not merely installed kernel packages.
  • Compare the running kernel against its distribution security advisory and fixed package release.
  • Confirm the applicable fix commit or documented backport is present.
  • After updating, verify systems rebooted into the remediated kernel.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

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CVE-2024-35811 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
3ADP providers
13Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.8CVSS 3.1HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H2.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

8.8High
CVSS 3.1 vector shape for CVE-2024-35811Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc
siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxe756af5b30b008f6ffcfebf8ad0b477f6f225b62, e756af5b30b008f6ffcfebf8ad0b477f6f225b62, e756af5b30b008f6ffcfebf8ad0b477f6f225b62, e756af5b30b008f6ffcfebf8ad0b477f6f225b62, e756af5b30b008f6ffcfebf8ad0b477f6f225b62, e756af5b30b008f6ffcfebf8ad0b477f6f225b62, e756af5b30b008f6ffcfebf8ad0b477f6f225b62, e756af5b30b008f6ffcfebf8ad0b477f6f225b62, e756af5b30b008f6ffcfebf8ad0b477f6f225b62unaffected
LinuxLinux3.7, 0, 4.19.312, 5.4.274, 5.10.215, 5.15.154, 6.1.84, 6.6.24, 6.7.12, 6.8.3, 6.9affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.