dbcve.org
Hardmac Wi Fi Soc FirmwareOperating system · Broadcom

CVE-2017-6956

HIGH · 8.8 CVSS v3.0 Published 2017-04-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
93/100
Remediation priority · Urgent
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
On the Broadcom Wi-Fi HardMAC SoC with fbt firmware, a stack buffer overflow occurs when handling an 802.11r (FT) authentication response, leading to remote code execution via a crafted access point that sends a long R0KH-ID field in a Fast BSS Transition Information Element (FT-IE).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Stack buffer overflow in Broadcom Wi-Fi HardMAC SoC firmware (fbt) when processing 802.11r Fast BSS Transition authentication responses. A malicious access point can trigger the overflow by sending an oversized R0KH-ID field within a crafted FT-IE (Fast BSS Transition Information Element), allowing remote code execution on the affected device.

MitigationApply firmware updates from Broadcom and device vendors once available. Until then, avoid connecting to untrusted or unknown wireless networks, as exploitation occurs during the 802.11r handshake with a malicious AP.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Hardmac Wi Fi Soc FirmwareOperating system
Affected:= 6.37.34.40

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Wi-Fi chipset vendor
    Check the device specifications or use commands like 'lspci', 'lsusb', or 'iw list' to identify the wireless network adapter. Look for Broadcom or Cypress (which acquired Broadcom's IoT business) in the output.
    Affected if The device does not use a Broadcom Wi-Fi HardMAC SoC chipset, then it is not affected.
  2. Check the Wi-Fi firmware version
    Depending on the device, use vendor-specific commands to retrieve the firmware version. On Linux systems, this may involve reading from /sys or using tools like 'brcmutil' or checking device-specific interfaces. The affected version is 6.37.34.40.
    Affected if The installed firmware version is exactly 6.37.34.40, the device is affected.
  3. Verify if 802.11r Fast BSS Transition is enabled
    Check the wireless interface configuration using 'iw' (e.g., 'iw dev <interface> info' or 'iw list' under 'Supported interface modes') or check the AP configuration settings for FT support. 802.11r must be enabled for the vulnerability to be triggerable.
    Affected if 802.11r Fast BSS Transition is disabled or not supported, the vulnerability cannot be triggered through normal operation.
  4. Determine if the device operates as a station (client) that roams
    Check if the device connects to multiple access points or is configured to roam. This vulnerability is triggered when the client device performs an FT handshake with a malicious AP during roaming.
    Affected if The device only operates as an AP or does not use roaming, the attack surface is reduced but the firmware vulnerability still exists if version matches.

The device is affected only if it uses Broadcom Wi-Fi HardMAC SoC firmware version 6.37.34.40 AND has 802.11r Fast BSS Transition enabled and is used as a client that can roam to untrusted networks.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply firmware updates from Broadcom and device vendors once available. Until then, avoid connecting to untrusted or unknown wireless networks, as exploitation occurs during the 802.11r handshake with a malicious AP.

Fix this in Hardmac Wi Fi Soc Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
16.0 hours of engineering $2,720
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,352.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2017-6956 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-6956 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data