CVE-2020-15635
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 network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6700 V1.0.4.84_10.0.58 routers with firmware 1.0.4.84_10.0.58. Authentication is not required to exploit this vulnerability. The specific flaw exists within the acsd service, which listens on TCP port 5916 by default. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the admin user. Was ZDI-CAN-9853.
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 confidenceA stack-based buffer overflow vulnerability in the acsd service (TCP port 5916) of NETGEAR R6700 routers allows remote attackers to execute arbitrary code without authentication. The flaw stems from insufficient validation of user-supplied data length before copying into a fixed-size stack buffer, enabling code execution in the admin user context.
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< 1.0.4.98CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:A/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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Confirm router model is R6700Access the router administration web interface (typically at 192.168.1.1) and navigate to the Status or Administration page to identify the device model, or inspect the physical device labelAffected if The device is a NETGEAR R6700 router (other models are not affected by this specific CVE)
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Check firmware versionIn the router admin panel, locate the firmware version displayed on the Status or Administration pageAffected if The installed firmware version is lower than 1.0.4.98 (versions 1.0.4.98 and higher contain the fix)
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Verify acsd service is runningScan the router from the LAN or WAN interface using a port scanner targeting TCP port 5916 (e.g., nmap -p 5916 <router_ip>), or check running services via telnet/SSH if enabledAffected if TCP port 5916 is open and responding on the router
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Check network exposure of port 5916Determine if port 5916 is accessible from the WAN/internet by scanning the router's public IP address, or review the router firewall settings in the admin panel under Port Forwarding/Port Triggering or Security settingsAffected if Port 5916 is accessible from an untrusted network (internet or untrusted LAN segment)
The router is affected if it is a NETGEAR R6700 running firmware version below 1.0.4.98 AND the acsd service on TCP port 5916 is accessible to the attacker.
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 data1.0.4.98
Apply the latest NETGEAR firmware update for the R6700 model. If no update is available, block TCP port 5916 at the network perimeter or disable the acsd service via router administration.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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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-2020-15635 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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- Version or environment caveats, and links to real fixes
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