CVE-2018-21203

Memory corruption via undisclosed stack overflow

Published Apr 28, 2020 · Updated Aug 5, 2024

Stack-based buffer overflow in affected NETGEAR router firmware allows remote attackers on an adjacent network to corrupt memory. NETGEAR has not published the vulnerable component, request type, or memory-copy operation that writes beyond the stack buffer. Exploitation requires no authentication or user interaction, but the available sources do not establish whether it crashes the router, executes code, or causes another concrete consequence.

CVSS severity8.8
High
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in affected NETGEAR router firmware allows remote attackers on an adjacent network to corrupt memory. NETGEAR has not published the vulnerable component, request type, or memory-copy operation that writes beyond the stack buffer. Exploitation requires no authentication or user interaction, but the available sources do not establish whether it crashes the router, executes code, or causes another concrete consequence.

The record

CVE
CVE-2018-21203
Published
Apr 28, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 28, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.8NETGEARCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.8NIST NVDAV:A/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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