CVE-2023-20169

Device reload via malformed IS-IS packet parsing

Published Aug 23, 2023 · Updated Aug 2, 2024

Denial of service in Cisco NX-OS Software 10.3(2) allows attackers to restart the IS-IS process and reload an affected device. The ingress parser insufficiently validates a crafted IS-IS packet, causing the IS-IS process to restart unexpectedly. Exploitation requires Layer 2 adjacency and IS-IS enabled on a Nexus 3000 or standalone-mode Nexus 9000; a successful packet can interrupt routing and reload the device.

CVSS severity7.4
High
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Denial of service in Cisco NX-OS Software 10.3(2) allows attackers to restart the IS-IS process and reload an affected device. The ingress parser insufficiently validates a crafted IS-IS packet, causing the IS-IS process to restart unexpectedly. Exploitation requires Layer 2 adjacency and IS-IS enabled on a Nexus 3000 or standalone-mode Nexus 9000; a successful packet can interrupt routing and reload the device.

The record

CVE
CVE-2023-20169
Published
Aug 23, 2023
Updated
Aug 2, 2024
Vendor
ClamAV
Product
Cisco NX-OS Software
Classifications
CWE-788, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=10.3(2)

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco NX-OS Softwareversion=10.3(2)

Published CVSS scores

7.4Cisco Systems, Inc.CVSS:3.1/AV:A/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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-788Access of Memory Location After End of Buffer
T1499Endpoint Denial of Service

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo