CVE-2021-20034: An improper access control vulnerability in SMA100 allows a remote unauthenticated attacker to bypass the path traversal checks and delete a
Noroxi assessment
Priority: This week (action score 61/100)
- Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 81.8% (FIRST EPSS); higher than 99.6% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to the record, no fixed version is available yet.
Don’t wait for the next maintenance window. Until a fix is released, restrict access to the affected component and 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
An improper access control vulnerability in SMA100 allows a remote unauthenticated attacker to bypass the path traversal checks and delete an arbitrary file potentially resulting in a reboot to factory default settings.
- Published
- Sep 27, 2021
- Updated
- Jun 16, 2026
- EPSS
- 81.8% · 99th percentile
- CWE
- CWE-284
Report tools
Action score
61
This week
Don’t wait for the next maintenance window.
- CVSS
- 36 / 40 · 9.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 25 / 30 · 81.8%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- Proof of concept exists, no weaponized module
- No fixed version yet
If any of these changes, we'll tell you in the daily email digest.
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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.
We use this product, ask for helpAffected 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 400 firmware | cpe:2.3:o:sonicwall:sma_400_firmware |
| sonicwall | sma 400 | cpe:2.3:h:sonicwall:sma_400 |
| sonicwall | sma 410 firmware | cpe:2.3:o:sonicwall:sma_410_firmware |
| sonicwall | sma 410 | cpe:2.3:h:sonicwall:sma_410 |
| sonicwall | sma 500v | cpe:2.3:a: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)
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- sonicwall sma 200 firmwareup to 9.0.0.10-28sv inclusive
- sonicwall sma 200 firmware10.2.0.0 and later · up to 10.2.0.7-34sv inclusive
- sonicwall sma 200 firmware10.2.1.0 and later · up to 10.2.1.0-17sv inclusive
- sonicwall sma 210 firmwareup to 9.0.0.10-28sv inclusive
- sonicwall sma 210 firmware10.2.0.0 and later · up to 10.2.0.7-34sv inclusive
- sonicwall sma 210 firmware10.2.1.0 and later · up to 10.2.1.0-17sv inclusive
- sonicwall sma 400 firmwareup to 9.0.0.10-28sv inclusive
- sonicwall sma 400 firmware10.2.0.0 and later · up to 10.2.0.7-34sv inclusive
- sonicwall sma 400 firmware10.2.1.0 and later · up to 10.2.1.0-17sv inclusive
- sonicwall sma 410 firmwareup to 9.0.0.10-28sv inclusive
- sonicwall sma 410 firmware10.2.0.0 and later · up to 10.2.0.7-34sv inclusive
- sonicwall sma 410 firmware10.2.1.0 and later · up to 10.2.1.0-17sv inclusive
- sonicwall sma 500vup to 9.0.0.10-28sv inclusive
- sonicwall sma 500v10.2.0.0 and later · up to 10.2.0.7-34sv inclusive
- sonicwall sma 500v10.2.1.0 and later · up to 10.2.1.0-17sv inclusive
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 SMA100
- 9.0.0.10-28sv and earlier, 10.2.0.7-34sv and earlier, 10.2.1.0-17sv and earlieraffected
Same product
sonicwall: all recordsOther 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 unauthenticKEV99Now
- CVE-2023-44221Improper neutralization of special elements in the SMA100 SSL-VPN management interface allows a remote authenticated attacker with administrKEV81Now
- CVE-2021-20039Improper neutralization of special elements in the SMA100 management interface '/cgi-bin/viewcert' POST http method allows a remote authenti59Plan
Published before and after this one in the same product
- Later →CVE-2021-20035Sep 27, 2021 · Improper neutralization of special elements in the SMA100 management interface allows a remote authenticated attacker to inject arbitrary coKEV57Plan
- 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 or38Monitor
- 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 /fileshare/sonicfile36Monitor
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
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Exploit-DB entry ×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.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | webapps | 2021-10-20 |
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.
- Published
- First PoC+22 d
- TodayNov 10, 2026+1870 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-284 · Improper Access ControlCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
nvd-primary
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)
- Embedding Scripts within ScriptsCAPEC-19likelihood: High · High
- Malicious Logic InsertionCAPEC-441likelihood: Medium · High
- Modification of Windows Service ConfigurationCAPEC-478likelihood: Low · High
- Malicious Root CertificateCAPEC-479likelihood: Low · Low
- Intent SpoofCAPEC-502
- WebView ExposureCAPEC-503
- Data Injected During ConfigurationCAPEC-536likelihood: Low · High
- Incomplete Data Deletion in a Multi-Tenant EnvironmentCAPEC-546likelihood: Low · Medium
ATT&CK techniques
- RootkitT1014
- Obfuscated Files or Information: Embedded PayloadsT1027.009
- Boot or Logon Initialization ScriptsT1037
- Taint shared contentT1080
- Server Software Component: Terminal Services DLLT1505.005
- Pre-OS Boot:BootkitT1542.003
- Create or Modify System ProcessT1543
- Create or Modify System Process: Launch AgentT1543.001
- Create or Modify System Process:Windows ServiceT1543.003
- Create or Modify System Process: Launch DaemonT1543.004
- Event Triggered Execution:Change Default File AssociationT1546.001
- Event Triggered Execution:.bash_profile and .bashrcT1546.004
- Event Triggered Execution: Accessibility FeaturesT1546.008
- Event Triggered Execution: Installer PackagesT1546.016
- Boot or Logon Autostart ExecutionT1547
- Boot or Logon Autostart Execution:Kernel Modules and ExtensionsT1547.006
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.