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Sma 200 Firmware CVE-2021-20034

CRITICAL
Improper Access Control (CWE-284)
2021-09-27 PSIRT@sonicwall.com
9.1
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Access control enforcement
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 9.1 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the critical-severity affected system.

Act Now Prioritize within 24-48h. Why: CRITICAL + EPSS > 30%, no patch available.
No patch listed yet 80.7% exploitation probability (EPSS)

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AnalysisAI

An improper access control vulnerability in SMA100 allows a remote unauthenticated attacker to bypass the path traversal checks and delete an arbitrary file potentially resulting in a reboot to. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-284. An improper access control vulnerability in SMA100 allows a remote unauthenticated attacker to bypass the path traversal checks and delete an arbitrary file potentially resulting in a reboot to factory default settings. Affected products include: Sonicwall Sma 200 Firmware, Sonicwall Sma 210 Firmware, Sonicwall Sma 400 Firmware, Sonicwall Sma 410 Firmware, Sonicwall Sma 500V.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.1 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High

DescriptionNVD

An improper access control vulnerability in SMA100 allows a remote unauthenticated attacker to bypass the path traversal checks and delete an arbitrary file potentially resulting in a reboot to factory default settings.

Threat Intelligence Overview

EPSS Score
80.7%
Top 0% exploitable
Exploit
POC
Public exploit code exists
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC Yes
EPSS 80.7%
Patch available No
Active threat Yes
Deciding rule
CRITICAL + EPSS > 30%, no patch available
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

147
Low Medium High Critical
KEV: 0
EPSS: +81
CVSS: +46
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Path traversal exploits occur when applications use user-controlled input to construct file system paths without proper validation.

Affected Products (CPE)NVD

cpe:2.3:o:sonicwall:sma_200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_210_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_210_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_210_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_400_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_400_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_400_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_410_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_410_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_410_firmware:*:*:*:*:*:*:*:*
cpe:2.3:a:sonicwall:sma_500v:*:*:*:*:*:*:*:*
cpe:2.3:a:sonicwall:sma_500v:*:*:*:*:*:*:*:*
cpe:2.3:a:sonicwall:sma_500v:*:*:*:*:*:*:*:*
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A Heap-based Buffer Overflow vulnerability in the SonicWall SMA100 appliance allows a remote authenticated attacker to c

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A post-authentication remote command injection vulnerability in SonicWall SMA100 allows a remote authenticated attacker

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