CVE-2018-21116

Adjacent unauthenticated code execution via stack overflow

Published Apr 22, 2020 · Updated Aug 5, 2024

Stack overflow in NETGEAR XR500 firmware before 2.3.2.32 allows remote attackers to execute arbitrary code without authentication. NETGEAR identifies a stack overflow but has not disclosed the affected handler, input field, or unsafe copy operation. Exploitation requires adjacent-network access, and successful exploitation grants full code execution on the router.

CVSS severity8.8
High
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack overflow in NETGEAR XR500 firmware before 2.3.2.32 allows remote attackers to execute arbitrary code without authentication. NETGEAR identifies a stack overflow but has not disclosed the affected handler, input field, or unsafe copy operation. Exploitation requires adjacent-network access, and successful exploitation grants full code execution on the router.

The record

CVE
CVE-2018-21116
Published
Apr 22, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 22, 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
5.8NIST NVDAV:A/AC:L/Au:N/C:P/I:P/A:P
8.8NETGEARCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1210Exploitation of Remote Services

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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