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.

Published: 2021-12-30 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20166 is rated High Risk (74.6/100): CVSS High severity, with high exploitation likelihood (EPSS 64.23%, 98th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +7.37% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-20166

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-08-27 56.86% 64.23% +7.37%
2 2025-08-21 36.23% 56.86% +20.63%
3 2025-08-20 — 36.23% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20166

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
5.8 2.0 MEDIUM
AV:A/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:A)
Requires access to an adjacent network segment.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 6.5 6.4 [email protected]

Weakness enumeration for CVE-2021-20166

Affected software / configurations for CVE-2021-20166

Vendor Product Version Raw CPE
netgear rax43_firmware 1.0.3.96 cpe:2.3:o:netgear:rax43_firmware:1.0.3.96:*:*:*:*:*:*:*

References for CVE-2021-20166

cvelogic Threat Intelligence