Threats / SonicWall / CVE-2021-20035
CVE-2021-20035
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
SonicWall SMA100 Appliances vulnerability
SonicWall SMA100 appliances contain an OS command injection vulnerability in the management interface allowing authenticated remote attackers to execute arbitrary commands.
Verdict
Today item — known-exploited.
A remote authenticated attacker can inject OS commands through the management interface of SonicWall SMA100 appliances, potentially achieving code execution with limited privileges. The vulnerability has been observed in active exploitation.
CISA KEV Yes · 2025-04-165EPSS 0.04181 (verify live)6CVSS 6.5 (CISA)4CISA SSVC Exploitation: active · Automatable: no · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
6 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-04-16).
Probability (EPSS)
EPSS 0.04181 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 6.5 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) · Affected: SonicWall, SMA100 Appliances. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-78 OS Command Injection — weakness family: Injection.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 1297 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I authenticate to the SMA100 management interface using valid credentials.
Business
Compromised or weak administrative credentials create an initial foothold for attackers.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I inject arbitrary OS commands through an input field in the management interface.
Business
The appliance fails to properly sanitize user input, allowing command injection attacks.
3
Lateral reach — past segmentation narrative 3
Attacker
I execute commands with 'nobody' user privileges to gather information or modify system configuration.
Business
Attackers gain code execution capability on security infrastructure, potentially bypassing access controls.
4
Data at risk — exfiltration narrative 4
Attacker
I leverage the execution context to escalate privileges or establish persistent access.
Business
The appliance becomes a pivot point for lateral movement within the network.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05