CVE-2024-20446Network attack vector

Remote device reload via malformed DHCPv6 reply

Published Aug 28, 2024 · Updated Aug 28, 2024

Denial of service in the DHCPv6 relay agent in Cisco NX-OS Software allows remote attackers to force an affected switch to reload. A DHCPv6 RELAY-REPLY message with malformed fields triggers a null pointer dereference in dhcp_snoop, causing repeated process crashes and a device reload. Exposure requires NX-OS Software 8.2(11), 9.3(9), 10.2(1), or 10.2(1q) on an affected Nexus switch with the relay agent enabled and an IPv6 address configured.

CVSS severity8.6
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

Denial of service in the DHCPv6 relay agent in Cisco NX-OS Software allows remote attackers to force an affected switch to reload. A DHCPv6 RELAY-REPLY message with malformed fields triggers a null pointer dereference in dhcp_snoop, causing repeated process crashes and a device reload. Exposure requires NX-OS Software 8.2(11), 9.3(9), 10.2(1), or 10.2(1q) on an affected Nexus switch with the relay agent enabled and an IPv6 address configured.

The record

CVE
CVE-2024-20446
Published
Aug 28, 2024
Updated
Aug 28, 2024
Vendor
ClamAV
Product
Cisco NX-OS Software
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.2(1)
  2. Affected versionversion=10.2(1q)
  3. Affected versionversion=8.2(11)
  4. Affected versionversion=9.3(9)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco NX-OS Softwareversion=10.2(1); version=10.2(1q); version=8.2(11); version=9.3(9)
ClamAV · Cisco NX-OSversion=10.2\(1\); version=10.2\(1q\); version=8.2\(11\); version=9.3\(9\)

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-476NULL Pointer Dereference
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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