CVE-2021-20042
CRITICALCVSS 9.8/10EPSS 2.66%
Last modified
CVE-2021-20042 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. EPSS estimates a 2.66% chance of exploitation in the next 30 days.
Description
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Sonicwall | Sma 200 Firmware | 9.0.0.11-31sv |
| Sonicwall | Sma 200 Firmware | 10.2.0.8-37sv |
| Sonicwall | Sma 200 Firmware | 10.2.1.1-19sv |
| Sonicwall | Sma 210 Firmware | 9.0.0.11-31sv |
| Sonicwall | Sma 210 Firmware | 10.2.0.8-37sv |
| Sonicwall | Sma 210 Firmware | 10.2.1.1-19sv |
| Sonicwall | Sma 410 Firmware | 9.0.0.11-31sv |
| Sonicwall | Sma 410 Firmware | 10.2.0.8-37sv |
| Sonicwall | Sma 410 Firmware | 10.2.1.1-19sv |
| Sonicwall | Sma 400 Firmware | 9.0.0.11-31sv |
| Sonicwall | Sma 400 Firmware | 10.2.0.8-37sv |
| Sonicwall | Sma 400 Firmware | 10.2.1.1-19sv |
| Sonicwall | Sma 500v Firmware | 9.0.0.11-31sv |
| Sonicwall | Sma 500v Firmware | 10.2.0.8-37sv |
| Sonicwall | Sma 500v Firmware | 10.2.1.1-19sv |
References
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-20042?
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.
How severe is CVE-2021-20042?
CVE-2021-20042 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 2.66% probability of exploitation in the next 30 days.
How do I fix CVE-2021-20042?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2021
- CVE-2021-20037SonicWall Global VPN Client 4.10.5 installer (32-bit and 64-…7.8
- CVE-2021-20038A Stack-based buffer overflow vulnerability in SMA100 Apache…9.8
- CVE-2021-20039Improper neutralization of special elements in the SMA100 ma…8.8
- CVE-2021-2004Vulnerability in the Siebel Core - Server BizLogic Script pr…4.3
- CVE-2021-20040A relative path traversal vulnerability in the SMA100 upload…7.5
- CVE-2021-20041An unauthenticated and remote adversary can consume all of t…7.5
- CVE-2021-20043A Heap-based buffer overflow vulnerability in SonicWall SMA1…8.8
- CVE-2021-20044A post-authentication remote command injection vulnerability…8.8
- CVE-2021-20045A buffer overflow vulnerability in SMA100 sonicfiles RAC_COP…9.8
- CVE-2021-20046A Stack-based buffer overflow in the SonicOS HTTP Content-Le…8.8
- CVE-2021-20047SonicWall Global VPN client version 4.10.6 (32-bit and 64-bi…7.8
- CVE-2021-20048A Stack-based buffer overflow in the SonicOS SessionID HTTP …8.8
Are you affected by CVE-2021-20042?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST