CVE-2018-21156

What it is

Certain NETGEAR devices are affected by a buffer overflow by an authenticated user. This affects D6220 before 1.0.0.38, D6400 before 1.0.0.74, D7000v2 before 1.0.0.74, D8500 before 1.0.3.39, DGN2200v4 before 1.0.0.102, DGN2200Bv4 before 1.0.0.102, EX3700 before 1.0.0.70, EX3800 before 1.0.0.70, EX6000 before 1.0.0.30, EX6100 before 1.0.2.22, EX6120 before 1.0.0.40, EX6130 before 1.0.0.22, EX6150 before 1.0.0.38, EX6200 before 1.0.3.86, EX7000 before 1.0.0.64, R6250 before 1.0.4.20, R6300v2 before 1.0.4.22, R6400 before 1.0.1.32, R6400v2 before 1.0.2.52, R6700 before 1.0.1.44, R6900 before 1.0.1.44, R6900P before 1.3.0.18, R7000 before 1.0.9.28, R7000P before 1.3.0.18, R7300DST before 1.0.0.62, R7900 before 1.0.2.10, R7900P before 1.3.0.10, R8000 before 1.0.4.12, R8000P before 1.3.0.10, R8300 before 1.0.2.116, R8500 before 1.0.2.116, WN2500RPv2 before 1.0.1.52, WNDR3400v3 before 1.0.1.18, and WNR3500Lv2 before 1.2.0.46.

At a glance

Exploitability

Can be exploited over the network with an admin-level account. High risk of data exposure, data tampering, service disruption.

Exploit odds

1.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2020-04-27 18:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 01:54 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.4% in the next 30 days (EPSS).
• Severity: 7.2 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2020-04-27 18:15 UTC

Last modified

2026-06-17 01:54 UTC

Exploit probability

1.4% · EPSS, next 30 days

Weakness

CWE-120 · Classic buffer overflow

Record status

Modified

Affected

• Netgear d6220 Firmware < 1.0.0.38
• Netgear d6400 Firmware < 1.0.0.74
• Netgear d7000 Firmware < 1.0.0.74
• Netgear d8500 Firmware < 1.0.3.39
• Netgear dgn2200 Firmware < 1.0.0.102
• Netgear dgn2200b Firmware < 1.0.0.102
• Netgear ex3700 Firmware < 1.0.0.70
• Netgear ex3800 Firmware < 1.0.0.70

Attack profile CVSS 3.1 · 7.2

Attack vector

Network

Complexity

Low

Privileges needed

High

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2018-21156.md and follow it. Check whether this project is affected by CVE-2018-21156. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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