CVE-2021-20016

SQL Injection in A SQL-Injection vulnerability in the SonicWall SSLVPN SMA100 product allows a remote unauthenticated attacker to perform SQL query to access username password and other session related information

Verified by Precogs Threat Research
Last Updated: Oct 31, 2025
Base Score
9.8CRITICAL

Executive Summary

CVE-2021-20016 is a critical severity vulnerability affecting appsec. It is classified as SQL Injection. This vulnerability is actively being exploited in the wild.

Precogs AI Insight

"A SQL injection vulnerability in SonicWall SSLVPN SMA100 allows unauthenticated remote attackers to extract sensitive data. Adversaries inject crafted SQL payloads to steal username and password hashes from the database. Precogs Application Security Module maps untrusted inputs directly to SQL execution sinks."

Exploit Probability (EPSS)
High (78.0%)
Public POC
Available
Exploit Probability
High (84%)
Public POC
Actively Exploited
Affected Assets
appsecCWE-89

What is this vulnerability?

CVE-2021-20016 is categorized as a critical SQL Injection flaw with a CVSS base score of 9.8. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

A SQL-Injection vulnerability in the SonicWall SSLVPN SMA100 product allows a remote unauthenticated attacker to perform SQL query to access username password and other session related information. This vulnerability impacts SMA100 build version 10.x.

This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.

Risk Assessment

MetricValue
CVSS Base Score9.8 (CRITICAL)
Vector StringCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
PublishedFebruary 4, 2021
Last ModifiedOctober 31, 2025
Related CWEsCWE-89, CWE-89

Impact on Systems

Data Exfiltration: Attackers can extract sensitive data from backend databases, configuration files, or internal services.

Authentication Bypass: Exploiting this flaw may allow unauthorized access to protected resources and administrative interfaces.

Lateral Movement: Once initial access is gained, attackers can pivot to internal systems and escalate privileges.

How to Fix and Mitigate CVE-2021-20016

  1. Apply Vendor Patches Immediately: This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog. Apply updates per vendor instructions.
  2. Verify Patch Deployment: Confirm all instances are updated using Precogs continuous monitoring.
  3. Review Audit Logs: Investigate historical access logs for indicators of compromise related to this attack surface.
  4. Implement Defense-in-Depth: Deploy WAF rules, network segmentation, and endpoint detection to limit blast radius.

Defending with Precogs AI

A SQL injection vulnerability in SonicWall SSLVPN SMA100 allows unauthenticated remote attackers to extract sensitive data. Adversaries inject crafted SQL payloads to steal username and password hashes from the database. Precogs Application Security Module maps untrusted inputs directly to SQL execution sinks.

Use Precogs to continuously scan your codebase, binaries, APIs, and infrastructure for this vulnerability class and related attack patterns. Our AI-powered detection engine combines static analysis with threat intelligence to identify exploitable weaknesses before attackers do.

Start scanning with Precogs →

Vulnerability Code Signature

Attack Data Flow

StageDetail
SourceUser-controlled HTTP request parameter
VectorString concatenation into SQL query string
SinkDatabase engine executes the malformed query
ImpactFull database compromise, unauthorized data modification or exfiltration

Vulnerable Code Pattern

# ❌ VULNERABLE: Direct string concatenation
def get_user(user_id):
    query = "SELECT * FROM users WHERE id = '" + user_id + "'"
    cursor.execute(query)  # Taint sink: unparameterized query
    return cursor.fetchone()

Secure Code Pattern

# ✅ SECURE: Parameterized query
def get_user(user_id):
    query = "SELECT * FROM users WHERE id = %s"
    cursor.execute(query, (user_id,))  # Sanitized binding
    return cursor.fetchone()

How Precogs Detects This

Precogs AI Analysis Engine traces data flow from HTTP request parameters through string concatenation directly into database execution sinks, identifying critical SQL injection vectors via Code Property Graph traversal.\n

Related Vulnerabilitiesvia CWE-89

Is your system affected?

Precogs AI detects CVE-2021-20016 in compiled binaries, LLMs, and application layers — even without source code access.