Threats / SonicWall / CVE-2021-20016
CVE-2021-20016
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
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.
CISA KEV Yes · 2021-11-035Ransomware use Flagged5EPSS 0.36952 (verify live)6CVSS 9.8 (CISA)4CISA SSVC Exploitation: active · Automatable: yes · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
27 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 0.36952 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) · Affected: SonicWall, SSLVPN SMA100. 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-89 SQL 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: yes · 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 273 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 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