Analyst readout for executives and security teams
Plain-English summary
This is a critical flaw in SonicWall SMA100 SSLVPN 10.x. An attacker on the network can exploit SQL injection without logging in and potentially access usernames, passwords, and session data. Because CISA lists it in KEV, treat exposed systems as urgent until verified remediated.
Executive priority
Handle as an emergency exposure review for any SonicWall SMA100 10.x deployment. The combination of unauthenticated network exploitation, credential/session data exposure, critical CVSS, and KEV status creates high business urgency.
Technical view
CVE-2021-20016 is a CWE-89 SQL injection in SonicWall SMA100 build version 10.x. The CVSS 3.1 score is 9.8, with network access, low complexity, no privileges, and no user interaction required. The described impact includes access to credential and session-related information.
Likely exposure
Organizations using SonicWall SMA100 SSLVPN build version 10.x are the named affected population. Risk is highest where the appliance is reachable from untrusted networks or the internet.
Exploitation context
Active exploitation is supported by CISA KEV listing for CVE-2021-20016. The source bundle does not provide exploit details, indicators of compromise, campaign attribution, or exploitation timelines.
Researcher notes
The bundle confirms affected product, version family, SQL injection class, CVSS vector, and KEV status. It does not include fixed build numbers, exploit indicators, or detection logic, so validation should rely on vendor advisories and environment telemetry.
Mitigation direction
- Identify all SonicWall SMA100 appliances and record exact build versions.
- Prioritize any SMA100 build version 10.x for urgent vendor-guided remediation.
- Review SonicWall PSIRT guidance before choosing patches, upgrades, or workarounds.
- Reduce unnecessary external exposure while remediation is pending.
- Treat credential and session data as potentially exposed until assessed.
Validation and detection
- Confirm whether any deployed SMA100 appliance runs build version 10.x.
- Check asset inventory against internet-facing SSLVPN entry points.
- Review authentication, session, and appliance logs for abnormal access patterns.
- Verify remediation status against SonicWall PSIRT guidance.
- Track this item in vulnerability management as CISA KEV-listed.
Public sources used
Based on public source material and reviewed before publication.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-89: Database access and collection lookup
Injection into data stores can inform collection, data access, and exfiltration detection reviews. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-20016 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0001CVE reference · x_refsource_CONFIRM
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20016CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.