CVE-2019-17147
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 · uneditedThis vulnerability allows remote attackers to execute arbitrary code on affected installations of TP-LINK TL-WR841N routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the web service, which listens on TCP port 80 by default. When parsing the Host request header, the process does not properly validate the length of user-supplied data prior to copying it to a fixed-length static buffer. An attacker can leverage this vulnerability to execute code in the context of the admin user. Was ZDI-CAN-8457.
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 · high confidenceBuffer overflow in TP-LINK TL-WR841N router web service (TCP port 80). The vulnerability exists in Host request header parsing where user-supplied data length is not validated before copying to a fixed-length buffer, allowing remote unauthenticated attackers to execute arbitrary code with admin privileges.
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= 0.9.1_4.16CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 the device modelAccess the router web interface or check the device label to confirm it is a TP-LINK TL-WR841N modelAffected if Device is not a TL-WR841N model, then not affected by this specific CVE
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Check the installed firmware versionLog into the router web interface (http://192.168.0.1 or http://192.168.1.1) and navigate to Status or System Tools > Firmware Upgrade page to view the current firmware versionAffected if Firmware version matches 0.9.1_4.16 exactly, then the device is running the affected version
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Verify the web service is enabledConfirm that the router web management interface is accessible on TCP port 80 (HTTP)Affected if The web interface is disabled and only HTTPS admin access is used, the attack surface is reduced but the vulnerability still exists in the firmware if it can be enabled
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Test Host header handling (optional)Send an HTTP GET request to the router with an abnormally long Host header (e.g., Host: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA) using a tool like curl or netcatAffected if The device crashes, reboots, or exhibits unexpected behavior in response to a long Host header, this may indicate the buffer overflow is present
The device is affected if it is a TL-WR841N router running firmware version 0.9.1_4.16 with the web interface accessible on port 80.
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 dataUpdate TP-LINK TL-WR841N firmware to vendor-patched version addressing this buffer overflow. If no update available, consider network segmentation or device replacement.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2019-17147 — 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-2019-17147 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
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