NVD / CVE Program· CNA sonicwall

CVE-2021-20039: Improper neutralization of special elements in the SMA100 management interface '/cgi-bin/viewcert' POST http method allows a remote…

HighCVSS 8.8 · v3.1—Weaponized No fix recorded

Noroxi assessment

Priority: Plan (action score 59/100)

A ready-made attack module is public (Metasploit); exploiting it takes no special expertise.
Probability of exploitation in the next 30 days: 78.7% (FIRST EPSS); higher than 99.5% of all records.
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.
Mentioned 2 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Add it to your regular patch cycle. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Improper neutralization of special elements in the SMA100 management interface '/cgi-bin/viewcert' POST http method allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.

Published: Dec 8, 2021
Updated: Jun 16, 2026
EPSS: 78.7% · 99th percentile
CWE: CWE-78

Report tools

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Action score

Plan

Add it to your regular patch cycle.

CVSS: 35 / 40 · 8.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 24 / 30 · 78.7%

CISA SSVC decision

Exploitation: proof of concept
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
Weaponized exploit exists
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
sonicwall	sma 200 firmware	cpe:2.3:o:sonicwall:sma_200_firmware
sonicwall	sma 200	cpe:2.3:h:sonicwall:sma_200
sonicwall	sma 210 firmware	cpe:2.3:o:sonicwall:sma_210_firmware
sonicwall	sma 210	cpe:2.3:h:sonicwall:sma_210
sonicwall	sma 410 firmware	cpe:2.3:o:sonicwall:sma_410_firmware
sonicwall	sma 410	cpe:2.3:h:sonicwall:sma_410
sonicwall	sma 400 firmware	cpe:2.3:o:sonicwall:sma_400_firmware
sonicwall	sma 400	cpe:2.3:h:sonicwall:sma_400
sonicwall	sma 500v firmware	cpe:2.3:o:sonicwall:sma_500v_firmware
sonicwall	sma 500v	cpe:2.3:h:sonicwall:sma_500v

Using sma 200 firmware? Add it to your stack and be the first to know about CVEs like this one. (VPN gateway)

Versions reported by the vendor

Affected version ranges reported by the assigning authority (sonicwall). Independent of NVD's CPE analysis and usually ahead of it.

SonicWall SonicWall SMA100
- 9.0.0.11-31sv and earlier, 10.2.0.8-37sv and earlier, 10.2.1.1-19sv and earlier, 10.2.1.2-24sv and earlieraffected

Affected versions · NVD (15)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

sonicwall sma 200 firmware10.2.0.8-37sv
sonicwall sma 200 firmware10.2.1.1-19sv
sonicwall sma 200 firmware9.0.0.11-31sv
sonicwall sma 210 firmware10.2.0.8-37sv
sonicwall sma 210 firmware10.2.1.1-19sv
sonicwall sma 210 firmware9.0.0.11-31sv
sonicwall sma 400 firmware10.2.0.8-37sv
sonicwall sma 400 firmware10.2.1.1-19sv
sonicwall sma 400 firmware9.0.0.11-31sv
sonicwall sma 410 firmware10.2.0.8-37sv
sonicwall sma 410 firmware10.2.1.1-19sv
sonicwall sma 410 firmware9.0.0.11-31sv
sonicwall sma 500v firmware10.2.0.8-37sv
sonicwall sma 500v firmware10.2.1.1-19sv
sonicwall sma 500v firmware9.0.0.11-31sv

Same product

sonicwall: all records

Other highest-scoring records for the same primary product.

CVE-2021-20038A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server's mod_cgi module environment variables allows a remote…KEV
99Now
CVE-2023-44221Improper neutralization of special elements in the SMA100 SSL-VPN management interface allows a remote authenticated attacker with…KEV
81Now
CVE-2021-20034An improper access control vulnerability in SMA100 allows a remote unauthenticated attacker to bypass the path traversal checks and delete…
61This week

Published before and after this one in the same product

← EarlierCVE-2021-20035Sep 27, 2021 · Improper neutralization of special elements in the SMA100 management interface allows a remote authenticated attacker to inject arbitrary…KEV
57Plan
Later →CVE-2021-20040Dec 8, 2021 · A relative path traversal vulnerability in the SMA100 upload funtion allows a remote unauthenticated attacker to upload crafted web pages…
38Monitor
Later →CVE-2021-20041Dec 8, 2021 · An unauthenticated and remote adversary can consume all of the device's CPU due to crafted HTTP requests sent to SMA100…
36Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

Metasploit module ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Metasploit module	exploit/linux/http/sonicwall_cve_2021_20039SonicWall SMA 100 Series Authenticated Command Injectionexploit	2021-12-14

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedDec 8, 2021
MetasploitDec 14, 2021+6 d
TodayNov 14, 2026+1802 d

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-22-0006 · Jan 4, 2022(SonicWall Güvenlik Zafiyeti)
TR-21-0978 · Dec 9, 2021(SonicWall Güvenlik Güncellemesi)

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

User input is inserted as text into a shell command. The shell may interpret special characters in the input as part of the command.

The bug in code

The whole CWE-78 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const host = req.body.host;
2exec("ping -c 1 " + host, onResult);

Fixed

1const host = req.body.host;
2if (!/^[a-z0-9.-]{1,253}$/i.test(host)) return res.sendStatus(400);
3execFile("ping", ["-c", "1", host], onResult);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log (0)

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026

Show all references (1 more)

attackerkb.com/topics/9szJhq46lw/cve-2021-20039/rapid7-analysis

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records