CVE-2020-28877
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 · uneditedBuffer overflow in in the copy_msg_element function for the devDiscoverHandle server in the TP-Link WR and WDR series, including WDR7400, WDR7500, WDR7660, WDR7800, WDR8400, WDR8500, WDR8600, WDR8620, WDR8640, WDR8660, WR880N, WR886N, WR890N, WR890N, WR882N, and WR708N.
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 confidenceBuffer overflow vulnerability in the copy_msg_element function of the devDiscoverHandle server component in TP-Link WR and WDR series routers. The overflow occurs when processing network messages, potentially allowing remote attackers to execute arbitrary code or cause denial of service.
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 dataall versionsall versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify your TP-Link router modelCheck the device label on the router or log into the web admin panel (typically at 192.168.0.1 or 192.168.1.1) and look for the model number displayed on the status or system information pageAffected if The model number matches WDR7400, WDR7500, WDR7660, WDR7800, WDR8400, WDR8500, WDR8600, or WDR8620
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Verify the firmware versionIn the web admin panel, navigate to System Tools > Firmware Upgrade or Status page and note the firmware version displayedAffected if The device is one of the affected models listed above - all firmware versions of these models are vulnerable
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Check if devDiscoverHandle service is accessibleFrom a computer on the local network, use a network scanner or run 'nmap -sU -p 9999 <router_ip>' to check if UDP port 9999 (common TP-Link discovery port) is open and respondingAffected if The devDiscoverHandle service port (commonly UDP 9999) is open and responds to discovery probes
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Verify network exposureCheck your router's firewall settings and determine if the device management interface or discovery service is accessible from the WAN/internet side (external networks)Affected if The router's management interface or discovery service is exposed directly to the internet or untrusted networks
You are affected if you are using any of the listed TP-Link WDR series models (WDR7400, WDR7500, WDR7660, WDR7800, WDR8400, WDR8500, WDR8600, WDR8620) with any firmware version, especially if the devDiscoverHandle service on UDP port 9999 is accessible from untrusted networks.
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 available TP-Link firmware updates for affected models (WDR7400, WDR7500, WDR7660, WDR7800, WDR8400, WDR8500, WDR8600, WDR8620, WDR8640, WDR8660, WR880N, WR886N, WR890N, WR882N, WR708N). If no patch is available, isolate affected devices behind a firewall or consider device replacement.
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-28877 — 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-2020-28877 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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