CVE-2021-20028
CVE-2021-20028 is a security flaw in SonicWall Secure Remote Access (SRA), SonicWall’s firewall and remote-access equipment. Attackers can read or change the database behind SonicWall Secure Remote Access (SRA). The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 28 Mar 2022, and says ransomware gangs have used it.[1]
SonicWall Secure Remote Access (SRA) is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. SonicWall has published a fix or advice.
Description
CISA calls it an SQL injection in SonicWall Secure Remote Access (SRA). In its words: “SonicWall Secure Remote Access (SRA) products contain an improper neutralization of a SQL Command leading to SQL injection.”[1]
The CVE record adds: “Improper neutralization of a SQL Command leading to SQL Injection vulnerability impacting end-of-life Secure Remote Access (SRA) products, specifically the SRA appliances running all 8.x firmware and 9.0.0.9-26sv or earlier”[2]
The underlying weakness is SQL injection (CWE-89), in MITRE’s list of common software weaknesses.
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; SonicWall’s advisory has them[3]. CISA names the product as SonicWall Secure Remote Access (SRA).
Most families won’t have SonicWall Secure Remote Access (SRA); it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 28 Mar 2022, 236 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 18 Apr 2022 to fix it.[1] CISA says ransomware gangs have used it.
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 30%. That’s in the top 2% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
SonicWall has published a fix or advice.[3] CISA’s required action: “The impacted product is end-of-life and should be disconnected if still in use.”[1]
- Check whether you use it.SonicWall Secure Remote Access (SRA) is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 18 Apr 2022 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks, noting that ransomware gangs have used it.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 30%.[4] |
See also
Other SonicWall flaws
- CVE-2026-83549, SonicWall SMA1000 Appliances: OS command injection ·
- CVE-2026-83548, SonicWall SMA1000 Appliances: server-side request forgery ·
- CVE-2026-15410, SonicWall SMA1000 Appliances: code injection ·
- CVE-2026-15409, SonicWall SMA1000 Appliances: server-side request forgery ·
- CVE-2025-40602, SonicWall SMA1000 appliance: sMA1000 missing authorization ·
Other SQL injection flaws
- CVE-2026-114625, Arista VeloCloud Orchestrator: SQL injection ·
- CVE-2026-76461, Cisco Secure Email Gateway: SQL injection ·
- CVE-2026-9586, Sangoma Switchvox: SQL injection ·
- CVE-2026-72898, Metabase: SQL injection ·
- CVE-2026-60137, WordPress Core: SQL injection ·
Added the same day
- CVE-2022-1096, Chrome and other Chromium browsers: type confusion ·
- CVE-2022-0543, Redis Debian-specific Redis Servers: debian-specific redis server lua sandbox escape ·
- CVE-2021-38646, Microsoft Office: access connectivity engine remote code execution ·
- CVE-2021-34486, Microsoft Windows: event tracing privilege escalation ·
- CVE-2021-26085, Atlassian Confluence Server: pre-authorization arbitrary file read ·
Every SonicWall flaw on CISA’s list · Everything added in March 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “SonicWall Secure Remote Access (SRA) SQL Injection Vulnerability”. Known Exploited Vulnerabilities Catalog, added 28 Mar 2022.
- ^ National Institute of Standards and Technology. “CVE-2021-20028 Detail”. National Vulnerability Database, published 4 Aug 2021.
- ^ SonicWall. Advisories and fixes: psirt.global.sonicwall.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.301, percentile 98.2, 31 Oct 2026.
- CVE Program. “CVE-2021-20028”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.