Software Development KitApplication · Mediatek

CVE-2025-20681

CRITICAL · 9.8 CVSS v3.1 Published 2025-07-08
Fix available
A fix is available. Upgrade to after 5.1.0.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable 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
In wlan AP driver, there is a possible out of bounds write due to an incorrect bounds check. This could lead to local escalation of privilege with User execution privileges needed. User interaction is not needed for exploitation. Patch ID: WCNCR00416936; Issue ID: MSV-3446.

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

Buffer overflow vulnerability in WLAN AP driver where an incorrect bounds check allows out-of-bounds write operations. This enables local privilege escalation from user-level execution to elevated privileges without requiring additional user interaction.

MitigationApply vendor patch WCNCR00416936 to affected WLAN AP driver implementations. Verify firmware/software versions against vendor advisory MSV-3446 and test wireless functionality post-patch.

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
Software Development KitApplication
Affected:<= 5.1.0.0
OpenwrtOperating system
Affected:= 19.07.0= 21.02.0

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

CVSS:3.1/AV:N/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 firmware or SDK platform
    Check the system information or firmware metadata to determine if the device runs Mediatek Software Development Kit or OpenWRT
    Affected if The system is identified as Mediatek SDK or OpenWRT
  2. Check Mediatek SDK version
    Query the SDK version through the system build information or firmware metadata (typically found in /etc/version, system info UI, or bootloader output)
    Affected if The reported version is 5.1.0.0 or lower
  3. Check OpenWRT version
    Query the OpenWRT version using 'cat /etc/openwrt_version' or 'cat /etc/os-release'
    Affected if The version reports exactly 19.07.0 or 21.02.0
  4. Confirm WLAN AP driver presence
    Check if the WLAN AP driver module is loaded or present on the system (e.g., lsmod, modinfo, or check for wireless driver files in /lib/modules)
    Affected if A Mediatek or vendor-specific WLAN AP driver is installed and active
  5. Verify wireless access point functionality is enabled
    Check if wireless AP mode is configured (review network configuration, hostapd status, or wireless interface settings)
    Affected if The device is configured as a wireless access point using the affected driver

A system is affected if it runs Mediatek SDK version 5.1.0.0 or lower, or OpenWRT version 19.07.0 or 21.02.0, and has the WLAN AP driver enabled with access point functionality active.

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
Upgrade available Upgrade to a release after 5.1.0.0
Interim mitigation

Apply vendor patch WCNCR00416936 to affected WLAN AP driver implementations. Verify firmware/software versions against vendor advisory MSV-3446 and test wireless functionality post-patch.

Fix this in Software Development Kit Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,808.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-20681 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2025-20681 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data