CVE-2021-20016
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.
- CVSS
- 9.8Criticalscored by CISA
- Exploited in the wild
- Yes, in CISA KEV since 3 Nov 2021CISA deadline for US federal agencies: 17 Nov 2021known use in ransomware campaigns
- EPSS
- 40.0%chance of exploitation in the next 30 daystop 2% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 4 Feb 2021analysed here 12 Nov 2026
Do first. Apply updates per vendor instructions. (CISA's required action for this KEV entry)
Summary
Triage
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| SonicWall SonicWall SMA100 | SMA100 build version 10.xVendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- sonicwall:sma_100_firmware
- sonicwall:sma_200_firmware
- sonicwall:sma_210_firmware
- sonicwall:sma_400_firmware
- sonicwall:sma_410_firmware
- sonicwall:sma_500v
Fix and mitigation
WAF and other mitigations
Can a WAF block it? Yes. SQL injection puts SQL syntax into a request parameter, and WAF signatures recognise that syntax well.
Also consider: parameterized queries · ORM
Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Listed since 3 Nov 2021. Known use in ransomware campaigns.
- CISA due date
- 17 Nov 2021, the remediation deadline for US federal agencies
- CISA required action
- Apply updates per vendor instructions.
- Public exploit code
- None on record in Exploit-DB, Metasploit, Nuclei templates or PoC-in-GitHub.
- CISA SSVC
- exploitation active, automatable yes, technical impact totalAssessed by CISA 5 Feb 2021 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
Timeline
- 4 Feb 2021Published
- 5 Feb 2021CISA SSVC assessment: exploitation active1 day later
- 3 Nov 2021Added to CISA KEV (exploited in the wild)271 days (about 9 months) later
- 17 Nov 2021CISA remediation due date (US federal agencies)14 days later
- 12 Aug 2026CVE record last updated1,729 days (about 5 years) later
- 12 Nov 2026Analysed by vulneraibility.com92 days (about 3 months) later
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
| Metric | Value | What it means |
|---|---|---|
| Attack vector | NetworkReachable over the internet or any routable network. | Reachable over the internet or any routable network. |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | NoneThe attacker needs no prior access. | The attacker needs no prior access. |
| User interaction | NoneNo victim action needed. | No victim action needed. |
| Scope | UnchangedImpact stays within the vulnerable component. | Impact stays within the vulnerable component. |
| Confidentiality | HighTotal data disclosure possible. | Total data disclosure possible. |
| Integrity | HighComplete modification possible. | Complete modification possible. |
| Availability | HighFull outage possible. | Full outage possible. |
Common questions
Is CVE-2021-20016 being exploited?
Yes. CVE-2021-20016 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2021-20016?
CVE-2021-20016 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2021-20016?
Yes. A fix has been recorded for CVE-2021-20016. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2021-20016 affect?
CVE-2021-20016 affects sonicwall:sma_100_firmware, sonicwall:sma_200_firmware, sonicwall:sma_210_firmware, sonicwall:sma_400_firmware, and 2 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
2 references in the CVE record, grouped by the tags the record gives them.
Other links (2)
- psirt.global.sonicwall.com /vuln-detail/SNWLID-2021-0001
- cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20016
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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