How severe is CVE-2021-20041?

CVE-2021-20041 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-20041 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20041?

CVE-2021-20041 primarily affects Sonicwall Sma 200 Firmware. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20041?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-20041 published?

CVE-2021-20041 was published on 2021-12-08 and last updated on 2026-06-17.

CVE-2021-20041

CVE-2021-20041 is a high-severity vulnerability in Sonicwall Sma 200 Firmware with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-835.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 7.8
EPSS exploit prediction: 7% (93rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-835
Affected product: Sonicwall Sma 200 Firmware
Published: 2021-12-08
Last modified: 2026-06-17

Description

An unauthenticated and remote adversary can consume all of the device's CPU due to crafted HTTP requests sent to SMA100 /fileshare/sonicfiles/sonicfiles resulting in a loop with unreachable exit condition. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.

Frequently asked questions

What is CVE-2021-20041?: An unauthenticated and remote adversary can consume all of the device's CPU due to crafted HTTP requests sent to SMA100 /fileshare/sonicfiles/sonicfiles resulting in a loop with unreachable exit condition. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.
How severe is CVE-2021-20041?: CVE-2021-20041 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-20041 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20041?: CVE-2021-20041 primarily affects Sonicwall Sma 200 Firmware. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20041?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-20041 published?: CVE-2021-20041 was published on 2021-12-08 and last updated on 2026-06-17.

References

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

Affected products (15)

cpe:2.3:o:sonicwall:sma_200_firmware:9.0.0.11-31sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_200_firmware:10.2.0.8-37sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_200_firmware:10.2.1.1-19sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_210_firmware:9.0.0.11-31sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_210_firmware:10.2.0.8-37sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_210_firmware:10.2.1.1-19sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_410_firmware:9.0.0.11-31sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_410_firmware:10.2.0.8-37sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_410_firmware:10.2.1.1-19sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_400_firmware:9.0.0.11-31sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_400_firmware:10.2.0.8-37sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_400_firmware:10.2.1.1-19sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_500v_firmware:9.0.0.11-31sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_500v_firmware:10.2.0.8-37sv:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_500v_firmware:10.2.1.1-19sv:*:*:*:*:*:*:*

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