Security Resilience

CVE-2021-20016

SQLi in Sonicwall Sma 100 Firmware 10.0.0.0 – 10.2.0.5-d-29sv

CISA KEVActive ExploitationEUVD ExploitedRansomware-linkedSQLi
Published
04 February 2021
Modified
12 August 2026
KEV Added
03 November 2021
Patch / advisory
View advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.40 99th percentile
Risk Priority 97 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2021-20016 is a critical-severity SQL Injection (CWE-89) vulnerability in Sonicwall Sma 100 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Protocol or Service Impersonation (T1001.003); ranked in the top 1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A SQL injection vulnerability tracked as CVE-2021-20016 affects the SonicWall SSLVPN SMA100 product on build version 10.x. The flaw, assigned CWE-89, permits construction and execution of arbitrary SQL queries against the application's database.

A remote unauthenticated attacker can exploit the issue over the network without any user interaction or credentials. Successful exploitation yields direct access to usernames, passwords, and other session-related data stored by the VPN appliance, corresponding to the maximum CVSS 3.1 base score of 9.8.

The vulnerability is documented in SonicWall PSIRT advisory SNWLID-2021-0001 and appears in the CISA Known Exploited Vulnerabilities catalog, indicating confirmed in-the-wild exploitation.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

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.

CWE(s)
CWE-89
KEV Date Added
03 November 2021

Related Threats

Threat-Actor AttributionAI

Microsoft Corp. (Salesforce / Slack engineer recruitment claims)
2021 Top Routinely Exploited Vulnerabilities | CISA
AnonOps
2021 Top Routinely Exploited Vulnerabilities | CISA

MITRE ATT&CK Enterprise Techniques

T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
attack.mitre.org →
T1003 OS Credential Dumping Credential Access
Adversaries may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password.
attack.mitre.org →
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
attack.mitre.org →
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2021-20028Same product: Sonicwall Sma 210both on KEV
CVE-2019-7481Same product: Sonicwall Sma 100both on KEV
CVE-2023-34133Same vendor: Sonicwall
CVE-2017-18362Shared CWE-89both on KEV
CVE-2021-44026Shared CWE-89both on KEV
CVE-2024-9465Shared CWE-89both on KEV
CVE-2023-34362Shared CWE-89both on KEV
CVE-2020-5722Shared CWE-89both on KEV
CVE-2024-43468Shared CWE-89both on KEV
CVE-2024-9379Shared CWE-89both on KEV

Affected Assets

sonicwall
sma 100 firmware
10.0.0.0 — 10.2.0.5-d-29sv
sonicwall
sma 200 firmware
all versions
sonicwall
sma 210 firmware
all versions
sonicwall
sma 400 firmware
all versions
sonicwall
sma 410 firmware
all versions
sonicwall
sma 500v
all versions

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V6.2.5

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-89

Penetration testing uses SQL injection payloads against database interfaces, identifying and supporting fixes for SQL injection weaknesses.

SI-10 Information Input Validation
addresses: CWE-89

Validates query inputs to prevent SQL syntax or command manipulation.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
blocks

Secure SDLC practices directly target injection flaws during coding and review so largely prevent CWE-89 introduction, yet the single broad outcome leaves residual risk from incomplete neutralization techniques or missed edge cases.

PR.AT-02 partial match
blocks

Training raises developer awareness of SQLi risks and can reduce introduction likelihood (partial) but removes none of the actual coding flaw's risk by itself since technical neutralization is still required.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.5.6 Contact with special interest groups partial match
blocks

A.5.6 only improves knowledge flow, awareness of threats/patches and access to specialist advice; it does not stop SQL injection from being exploitable in code that still contains the flaw.

References