CVE-2021-20042
An unauthenticated remote attacker can use SMA 100 as an unintended proxy or intermediary...
An unauthenticated remote attacker can use SMA 100 as an unintended proxy or intermediary undetectable proxy to bypass firewall rules. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
An unauthenticated remote attacker can use SMA 100 as an unintended proxy or intermediary undetectable proxy to bypass firewall rules. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.
- Record
CVE-2021-20042- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-441
- Updated
- 2026-11-02
CVE List No score
An unauthenticated remote attacker can use SMA 100 as an unintended proxy or intermediary undetectable proxy to bypass firewall rules. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.
- Record
CVE-2021-20042- Weakness
- CWE-441
- Updated
- 2026-11-02
EUVDEUVD-2021-7505 No score
An unauthenticated remote attacker can use SMA 100 as an unintended proxy or intermediary undetectable proxy to bypass firewall rules. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.
- Record
EUVD-2021-7505- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-7jhp-ff4f-8fx7
An unauthenticated remote attacker can use SMA 100 as an unintended proxy or intermediary...
An unauthenticated remote attacker can use SMA 100 as an unintended proxy or intermediary undetectable proxy to bypass firewall rules. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.
- Record
GHSA-7jhp-ff4f-8fx7- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-441, CWE-610
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-20042 is a critical vulnerability (CVSS 9.8) in Sonicwall Sma 200 Firmware, published December 8, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 3.68%, the 89th percentile. No source names a fixed version.