CVE-2026-31267
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 · uneditedMercusys MW302R MW302R(EU)_V1_1.4.10 Build 231023 is vulnerable to Buffer Overflow in the administrative web interface. A stack buffer overflow vulnerability in the administrative web interface allows an authenticated attacker with administrative privileges to trigger a system crash by sending a specially crafted request. The vulnerability results in denial of service through control flow manipulation to an arbitrary instruction address.
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 stack buffer overflow vulnerability exists in the administrative web interface of Mercusys MW302R firmware version MW302R(EU)_V1_1.4.10 Build 231023. An authenticated attacker with administrative privileges can send a specially crafted request that overflows a stack buffer, allowing control flow manipulation to arbitrary instruction addresses and causing system crash (denial of service).
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:L/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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Identify the router modelCheck the device label or web interface for the model number to confirm it is a Mercusys MW302R routerAffected if The device is a Mercusys MW302R router
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Check the firmware versionAccess the administrative web interface and navigate to the status or firmware upgrade page to view the current firmware version, or check the vendor support page for firmware version informationAffected if The firmware version is MW302R(EU)_V1_1.4.10 Build 231023 or an earlier version from the same release line
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Confirm administrative web interface accessibilityAttempt to access the router administrative web interface via HTTP/HTTPS on the default IP address (typically 192.168.1.1) from a browserAffected if The administrative web interface is reachable from an untrusted network or the interface responds to requests
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Verify administrative account statusCheck if an administrative account is configured or active on the router by examining the user management or administration settings in the web interfaceAffected if An administrative account with privileges exists and is enabled
You are affected if you have a Mercusys MW302R router running firmware version MW302R(EU)_V1_1.4.10 Build 231023 and the administrative web interface is accessible with valid admin credentials.
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 vendor-supplied firmware patch when available; until then, restrict administrative web interface access to trusted networks or IP addresses only, and consider network segmentation to limit exposure.
- Consultation4.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,152.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-31267 — 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-2026-31267 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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