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Fastconnect 6700 FirmwareOperating system · Qualcomm

CVE-2025-21439

HIGH · 7.8 CVSS v3.1 Published 2025-04-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
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
Memory corruption may occur while reading board data via IOCTL call when the WLAN driver copies the content to the provided output buffer.

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 · moderate confidence

Memory corruption vulnerability in WLAN driver during IOCTL call for reading board data. The driver copies data to an output buffer without proper size validation, leading to potential buffer overflow and memory corruption.

MitigationApply vendor driver update that implements proper bounds checking on output buffer size before memory copy operations in the affected IOCTL handler.

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
Fastconnect 6700 FirmwareOperating system
Affected:all versions
Fastconnect 6900 FirmwareOperating system
Affected:all versions
Qca6595au FirmwareOperating system
Affected:all versions
Qcm5430 FirmwareOperating system
Affected:all versions
Qcm6490 FirmwareOperating system
Affected:all versions
Qcn7605 FirmwareOperating system
Affected:all versions
Qcn7606 FirmwareOperating system
Affected:all versions
Qcs5430 FirmwareOperating system
Affected:all versions

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 Qualcomm WLAN hardware present
    On Linux, run 'lspci | grep -i network' or 'lspci | grep -i wireless' to list wireless adapters. On Windows, open Device Manager and expand Network adapters. Look for devices with Qualcomm Fastconnect, QCA, QCM, QCN, or QCS branding.
    Affected if Any adapter listed matches the affected product names: Fastconnect 6700, Fastconnect 6900, Qca6595au, Qcm5430, Qcm6490, Qcn7605, Qcn7606, or Qcs5430
  2. Check WLAN driver version on Linux
    Run 'lsmod | grep -i ath' or 'lsmod | grep -i qca' to find loaded wireless modules. Then check driver details with 'modinfo <module_name>' or check firmware version with 'dmesg | grep -i firmware' and 'iw dev' commands.
    Affected if The driver or firmware version corresponds to the affected Qualcomm product families listed in the CVE
  3. Verify IOCTL interface availability
    On Linux, check if the wireless driver exposes IOCTL interfaces by examining /proc/net/wireless or using 'iw list' to enumerate driver capabilities. On Windows, this requires checking driver properties in Device Manager or using driver-specific diagnostic tools from the vendor.
    Affected if The wireless driver exposes IOCTL handlers for reading board data (often related to NVRAM or calibration data retrieval)
  4. Check system logs for driver errors
    Review system logs (dmesg, journalctl -b | grep -i ath, or Windows Event Viewer under System/Application logs) for any crash reports, memory corruption indicators, or driver-generated error messages related to IOCTL operations.
    Affected if Logs contain entries referencing buffer overflow, memory corruption, or IOCTL failures in the WLAN driver context

A system is affected if it contains any of the listed Qualcomm wireless hardware components (Fastconnect 6700/6900, Qca6595au, Qcm5430, Qcm6490, Qcn7605, Qcn7606, or Qcs5430) with the vulnerable driver version, as all versions of these products are impacted by the insufficient size validation in the IOCTL handler for board data.

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 vendor driver update that implements proper bounds checking on output buffer size before memory copy operations in the affected IOCTL handler.

Fix this in Fastconnect 6700 Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,100
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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-2025-21439 in production — separate from our analysis above.

No notes yet

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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
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