CVE-2021-20035

Exp

Improper neutralization of special elements in the SMA100 management interface allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user which potentially leads to DoS.

Published: 2021-09-27 Last update: 2025-10-31 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20035 is rated Critical Active Threat (83.6/100): CVSS Medium severity, with high exploitation likelihood (EPSS 12.84%, 94th percentile). CISA KEV confirms active exploitation (added 2025-04-16) affecting SonicWall / SMA100 Appliances. a weakness (CWE-78) Unauthenticated remote administrative access may be possible. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2021-20035

Name: SonicWall SMA100 Appliances OS Command Injection Vulnerability · CISA KEV detail

Exploit added: 2025-04-16

Action due: 2025-05-07

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Exploit prediction scoring system (EPSS) score for CVE-2021-20035

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-26 13.18% 12.84% -0.34%
2 2026-05-25 3.97% 13.18% +9.21%
3 2026-05-06 — 3.97% —

Full EPSS history (39 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20035

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0
6.8 2.0 MEDIUM
AV:N/AC:L/Au:S/C:N/I:N/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:C)
Complete availability impact.
 8.0 6.9 [email protected]

Weakness enumeration for CVE-2021-20035

Affected software / configurations for CVE-2021-20035

Vendor Product Version Raw CPE
sonicwall sma_200_firmware < 9.0.0.11-31sv cpe:2.3:o:sonicwall:sma_200_firmware:*:*:*:*:*:*:*:*
sonicwall sma_200_firmware >= 10.2.0.0, < 10.2.0.8-37sv cpe:2.3:o:sonicwall:sma_200_firmware:*:*:*:*:*:*:*:*
sonicwall sma_200_firmware >= 10.2.1.0, < 10.2.1.1-19sv cpe:2.3:o:sonicwall:sma_200_firmware:*:*:*:*:*:*:*:*
sonicwall sma_210_firmware < 9.0.0.11-31sv cpe:2.3:o:sonicwall:sma_210_firmware:*:*:*:*:*:*:*:*
sonicwall sma_210_firmware >= 10.2.0.0, < 10.2.0.8-37sv cpe:2.3:o:sonicwall:sma_210_firmware:*:*:*:*:*:*:*:*
sonicwall sma_210_firmware >= 10.2.1.0, < 10.2.1.1-19sv cpe:2.3:o:sonicwall:sma_210_firmware:*:*:*:*:*:*:*:*
sonicwall sma_400_firmware < 9.0.0.11-31sv cpe:2.3:o:sonicwall:sma_400_firmware:*:*:*:*:*:*:*:*
sonicwall sma_400_firmware >= 10.2.0.0, < 10.2.0.8-37sv cpe:2.3:o:sonicwall:sma_400_firmware:*:*:*:*:*:*:*:*
sonicwall sma_400_firmware >= 10.2.1.0, < 10.2.1.1-19sv cpe:2.3:o:sonicwall:sma_400_firmware:*:*:*:*:*:*:*:*
sonicwall sma_410_firmware < 9.0.0.11-31sv cpe:2.3:o:sonicwall:sma_410_firmware:*:*:*:*:*:*:*:*
sonicwall sma_410_firmware >= 10.2.0.0, < 10.2.0.8-37sv cpe:2.3:o:sonicwall:sma_410_firmware:*:*:*:*:*:*:*:*
sonicwall sma_410_firmware >= 10.2.1.0, < 10.2.1.1-19sv cpe:2.3:o:sonicwall:sma_410_firmware:*:*:*:*:*:*:*:*
sonicwall sma_500v < 9.0.0.11-31sv cpe:2.3:a:sonicwall:sma_500v:*:*:*:*:*:*:*:*
sonicwall sma_500v >= 10.2.0.0, < 10.2.0.8-37sv cpe:2.3:a:sonicwall:sma_500v:*:*:*:*:*:*:*:*
sonicwall sma_500v >= 10.2.1.0, < 10.2.1.1-19sv cpe:2.3:a:sonicwall:sma_500v:*:*:*:*:*:*:*:*

References for CVE-2021-20035

cvelogic Threat Intelligence