Cyber 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
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 0.37 98th percentile
Risk Priority 97 floored blend · peak EPSS

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 Exploit Public-Facing Application (T1190); ranked in the top 2% 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)

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)
KEV Date Added
03 November 2021

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
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-2016-2386Shared CWE-89both on KEV
CVE-2024-6670Shared CWE-89both on KEV
CVE-2024-29824Shared CWE-89both on KEV
CVE-2020-12271Shared CWE-89both on KEV
CVE-2020-29574Shared CWE-89both on KEV
CVE-2021-44026Shared 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.

addresses: CWE-89

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

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
prevents

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
prevents

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.

finds

The same secure-coding and static-analysis activities surface missing neutralization of SQL metacharacters before the system is accepted.

prevents

Early warnings and shared best-practice information help organizations apply the latest remediation techniques against SQL-injection vulnerabilities.

prevents

Threat-intelligence feeds that surface new SQL-injection campaigns enable rapid updates to query-construction defenses and detection signatures before exploitation occurs.

prevents

Secure-coding rules and security testing phases mandate the use of parameterized queries or equivalent escaping, preventing the construction of dynamic SQL statements from untrusted input.

prevents

Language-specific secure coding rules, peer review and SAST together prevent the construction of SQL statements from untrusted data without proper parameterization or escaping.

References