CVE-2021-20045Network attack vector

Unauthenticated code execution via unchecked buffer copies

Published Dec 8, 2021 · Updated Aug 3, 2024

Buffer overflows in SonicWall SMA 100 firmware allow remote attackers to execute code as the nobody user without authentication. The RAC_COPY_TO method passes attacker-controlled User, Pass, and Domn parameters to fileexplorer, where unchecked strcpy calls copy them into fixed-size stack and heap buffers. Successful exploitation runs arbitrary code with the appliance's nobody-user privileges.

CVSS severity9.8
Critical
EPSS probability25.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflows in SonicWall SMA 100 firmware allow remote attackers to execute code as the nobody user without authentication. The RAC_COPY_TO method passes attacker-controlled User, Pass, and Domn parameters to fileexplorer, where unchecked strcpy calls copy them into fixed-size stack and heap buffers. Successful exploitation runs arbitrary code with the appliance's nobody-user privileges.

The record

CVE
CVE-2021-20045
Published
Dec 8, 2021
Updated
Aug 3, 2024
Vendor
SonicWall
Product
Secure Mobile Access (SMA) 100 Series
Classifications
CWE-120, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=10.2.0.8-37sv and earlier
  2. Affected versionversion=10.2.1.1-19sv and earlier
  3. Affected versionversion=10.2.1.2-24sv and earlier

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SonicWall · Secure Mobile Access (SMA) 100 Seriesversion=10.2.0.8-37sv and earlier; version=10.2.1.1-19sv and earlier; version=10.2.1.2-24sv and earlier

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

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')
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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