How severe is CVE-2021-20166?

CVE-2021-20166 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-20166 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20166?

CVE-2021-20166 affects Netgear Rax43 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-20166?

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-2021-20166 published?

CVE-2021-20166 was published on 2021-12-30 and last updated on 2026-06-17.

CVE-2021-20166

CVE-2021-20166 is a high-severity vulnerability in Netgear Rax43 Firmware with a CVSS 3.x base score of 8.8. 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-120.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 5.8
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Netgear Rax43 Firmware
Published: 2021-12-30
Last modified: 2026-06-17

Description

Netgear RAX43 version 1.0.3.96 contains a buffer overrun vulnerability. The URL parsing functionality in the cgi-bin endpoint of the router containers a buffer overrun issue that can redirection control flow of the applicaiton.

Frequently asked questions

What is CVE-2021-20166?: Netgear RAX43 version 1.0.3.96 contains a buffer overrun vulnerability. The URL parsing functionality in the cgi-bin endpoint of the router containers a buffer overrun issue that can redirection control flow of the applicaiton.
How severe is CVE-2021-20166?: CVE-2021-20166 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-20166 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20166?: CVE-2021-20166 affects Netgear Rax43 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-20166?: 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-2021-20166 published?: CVE-2021-20166 was published on 2021-12-30 and last updated on 2026-06-17.

References

https://www.tenable.com/security/research/tra-2021-55

Affected products (1)

cpe:2.3:o:netgear:rax43_firmware:1.0.3.96:*:*:*:*:*:*:*

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