CVE-2026-20419
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 · uneditedIn wlan AP/STA firmware, there is a possible system becoming irresponsive due to an uncaught exception. This could lead to remote (proximal/adjacent) denial of service with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: WCNCR00461663 / WCNCR00463309; Issue ID: MSV-4852.
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 confidenceA denial of service vulnerability exists in WLAN AP/STA firmware where an uncaught exception causes the system to become unresponsive. The flaw is exploitable remotely by an attacker with proximal/adjacent network access (within WiFi range) without requiring authentication or user interaction.
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<= 3.6<= 7.6.7.2= 19.07.0= 21.02.0CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Check Mediatek NBIoT SDK versionReview SDK documentation, release notes, or check the SDK version file (such as version.h or sdk_version.txt) in the development environmentAffected if The SDK version is 3.6 or lower
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Check Mediatek Software Development Kit versionReview SDK documentation, release notes, or check the SDK version file in the development environment or firmware build systemAffected if The SDK version is 7.6.7.2 or lower
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Check OpenWrt version on deviceRun 'cat /etc/openwrt_release' or 'cat /etc/os-release' on the device to retrieve the installed OpenWrt versionAffected if The installed version is exactly 19.07.0 or 21.02.0
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Verify WLAN AP/STA functionality is in useCheck if WiFi interfaces are configured and active using 'iwconfig' or 'uci show wireless' on the deviceAffected if Wireless AP or STA mode is enabled and the device uses one of the affected firmware versions
A system is affected if it runs Mediatek NBIoT SDK <= 3.6, Mediatek SDK <= 7.6.7.2, or OpenWrt 19.07.0/21.02.0 with WiFi functionality enabled.
Generated from the published advisory. Verify against your own configuration.
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 dataApply the vendor firmware patch (WCNCR00461663 or WCNCR00463309) to all affected devices. If no patch is available, network segmentation and monitoring for device unresponsiveness may help mitigate the impact.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-20419 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-20419 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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