CVE-2023-20080Network attack vector

Device reload via malformed DHCPv6 messages

Published Mar 23, 2023 · Updated Oct 28, 2024

Denial of service in Cisco IOS DHCPv6 features allows remote attackers to reload affected devices with crafted DHCPv6 messages. The DHCPv6 message-processing path insufficiently validates data boundaries, allowing an out-of-range array index during relay or server handling. Exposure requires IPv6 routing, an IPv6-addressed interface, and a DHCPv6 relay or server configuration, all disabled by default; the result is a device reboot and service interruption.

CVSS severity8.6
High
EPSS probability0.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cisco IOS DHCPv6 features allows remote attackers to reload affected devices with crafted DHCPv6 messages. The DHCPv6 message-processing path insufficiently validates data boundaries, allowing an out-of-range array index during relay or server handling. Exposure requires IPv6 routing, an IPv6-addressed interface, and a DHCPv6 relay or server configuration, all disabled by default; the result is a device reboot and service interruption.

The record

CVE
CVE-2023-20080
Published
Mar 23, 2023
Updated
Oct 28, 2024
Vendor
ClamAV
Product
Cisco IOS
Classifications
CWE-129, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 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?

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  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco IOSversion=n/a

Published CVSS scores

8.6Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-129Improper Validation of Array Index
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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