How severe is CVE-2021-20034?

CVE-2021-20034 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2021-20034 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 81% (100th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20034?

CVE-2021-20034 primarily affects Sonicwall Sma 200 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20034?

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

When was CVE-2021-20034 published?

CVE-2021-20034 was published on 2021-09-27 and last updated on 2026-06-17.

CVE-2021-20034

CVE-2021-20034 is a critical-severity vulnerability in Sonicwall Sma 200 Firmware with a CVSS 3.x base score of 9.1. Its EPSS exploit-prediction score of 81% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-22.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 81% (100th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Sonicwall Sma 200 Firmware
Published: 2021-09-27
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-20034?: 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.
How severe is CVE-2021-20034?: CVE-2021-20034 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2021-20034 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 81% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20034?: CVE-2021-20034 primarily affects Sonicwall Sma 200 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20034?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-20034 published?: CVE-2021-20034 was published on 2021-09-27 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:o:sonicwall:sma_200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_210_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_400_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:sonicwall:sma_410_firmware:*:*:*:*:*:*:*:*
cpe:2.3:a:sonicwall:sma_500v:*:*:*:*:*:*:*:*

More vulnerabilities in Sonicwall Sma 200 Firmware

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