CVE-2021-20035
MediumExploitedPublic exploitImproper neutralization of special elements in the SMA100 management interface allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user which potentially leads to DoS.
Published Sep 27, 2021 · Updated Oct 31, 2025
Key Facts
Patch immediately- CVE-2021-20035 is a medium-severity vulnerability (CVSS 6.5 v3.1) affecting Sma 500v (Sonicwall), Sma 200 Firmware (Sonicwall), Sma 210 Firmware (Sonicwall) and 3 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Apr 15, 2025. Public exploit code is available.
- EPSS estimates a 4.2% probability of exploitation in the next 30 days.
- Fixed versions are available, including Sma 200 Firmware 9.0.0.11-31sv, Sma 210 Firmware 9.0.0.11-31sv, Sma 400 Firmware 9.0.0.11-31sv.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
6.5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS (30-day exploit likelihood)
4.2%
Higher than 90.7% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-20035 brief as a PDF
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Description
Improper neutralization of special elements in the SMA100 management interface allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user which potentially leads to DoS.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Apr 16, 2025 | May 7, 2025 | Not reported |
| Industry KEV feed | Apr 15, 2025 | May 7, 2025 | Not reported |
| CIRCL KEV | Apr 16, 2025 | May 7, 2025 | Not reported |
| ENISA EUVD | Apr 16, 2025 | n/a | Not reported |
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Affected Products
6 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Sma 500vSonicwall | See advisory | 9.0.0.11-31sv |
| Sma 200 FirmwareSonicwall | See advisory | 9.0.0.11-31sv |
| Sma 210 FirmwareSonicwall | See advisory | 9.0.0.11-31sv |
| Sma 400 FirmwareSonicwall | See advisory | 9.0.0.11-31sv |
| Sma 410 FirmwareSonicwall | See advisory | 9.0.0.11-31sv |
Patched Releases
Sma 200 Firmware
9.0.0.11-31sv
Sma 210 Firmware
9.0.0.11-31sv
Sma 400 Firmware
9.0.0.11-31sv
Sma 410 Firmware
9.0.0.11-31sv
Sma 500v
9.0.0.11-31sv
Timeline
Publicly disclosed
Sep 27, 2021
Added to Industry KEV feed
Apr 15, 2025
Added to CISA KEV
Apr 16, 2025
Added to CIRCL KEV
Apr 16, 2025
Added to ENISA EUVD
Apr 16, 2025
Last updated
Oct 31, 2025
Weakness Type
- CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
References
- advisoryVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
Improper neutralization of special elements in the SMA100 management interface allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user which potentially leads to DoS.
Affected: Sma 500v (Sonicwall); Sma 200 Firmware (Sonicwall); Sma 210 Firmware (Sonicwall), among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Apr 15, 2025.
Yes. It was added on Apr 16, 2025 with a federal remediation due date of May 7, 2025.
Public exploit code is available.
Fixed versions are available, including Sma 200 Firmware 9.0.0.11-31sv, Sma 210 Firmware 9.0.0.11-31sv, Sma 400 Firmware 9.0.0.11-31sv.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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