Threats / SonicWall / CVE-2021-20016
CVE-2021-20016
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
SonicWall SSLVPN SMA100 vulnerability
SonicWall SSLVPN SMA100 contains a SQL injection vulnerability allowing unauthenticated remote attackers to access credentials. The vulnerability has been exploited in the wild and linked to ransomware campaigns.
Verdict
Today item, not a backlog item.
This SQL injection vulnerability in a widely-deployed VPN appliance presents critical risk due to unauthenticated exploitation, credential exposure, and documented active exploitation in ransomware operations.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
26 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 2021-11-03), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.40038 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: SonicWall, SSLVPN SMA100. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-89 SQL Injection — weakness family: Injection.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
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 craft malicious SQL queries in unauthenticated requests to the SMA100 interface to extract stored credentials from the backend database.
Business
Attackers gain valid VPN credentials without authentication, enabling unauthorized network access and lateral movement.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I use harvested credentials to authenticate to the VPN and establish persistent remote access to the organization's internal network.
Business
The organization's network perimeter is compromised, allowing threat actors to move laterally and establish footholds for further attacks.
3
Lateral reach — past segmentation narrative 3
Attacker
I deploy ransomware payloads across the compromised internal network to encrypt critical systems and data.
Business
Operations are disrupted, data is held for ransom, and recovery costs and downtime mount significantly.
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