CVE-2021-1300Network attack vector

Root code execution via crafted IP traffic

Published Jan 20, 2021 · Updated Nov 12, 2024

Buffer overflow in Cisco SD-WAN Software allows remote attackers to execute arbitrary code as root by sending crafted IP traffic through a device. The traffic-processing path handles crafted IP packets incorrectly, overflowing a memory buffer as the packets traverse an affected device. No authentication or user interaction is required, and successful exploitation grants root-level control of the underlying operating system.

CVSS severity9.8
Critical
EPSS probability2.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Cisco SD-WAN Software allows remote attackers to execute arbitrary code as root by sending crafted IP traffic through a device. The traffic-processing path handles crafted IP packets incorrectly, overflowing a memory buffer as the packets traverse an affected device. No authentication or user interaction is required, and successful exploitation grants root-level control of the underlying operating system.

The record

CVE
CVE-2021-1300
Published
Jan 20, 2021
Updated
Nov 12, 2024
Vendor
ClamAV
Product
Cisco SD-WAN
Classifications
CWE-120, CWE-119, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 12, 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=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco SD-WANversion=n/a

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8Cisco Systems, Inc.CVSS:3.0/AV:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1190Exploit Public-Facing Application

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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