How severe is CVE-2018-21121?

CVE-2018-21121 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-2018-21121 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-21121?

CVE-2018-21121 primarily affects Netgear Gs810emx Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-21121?

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-2018-21121 published?

CVE-2018-21121 was published on 2020-04-22 and last updated on 2026-06-17.

CVE-2018-21121

CVE-2018-21121 is a high-severity vulnerability in Netgear Gs810emx 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-287.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 5.8
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Netgear Gs810emx Firmware
Published: 2020-04-22
Last modified: 2026-06-17

Description

Certain NETGEAR devices are affected by authentication bypass. This affects GS810EMX before 1.0.0.5, XS512EM before 1.0.0.6, and XS724EM before 1.0.0.6.

Frequently asked questions

What is CVE-2018-21121?: Certain NETGEAR devices are affected by authentication bypass. This affects GS810EMX before 1.0.0.5, XS512EM before 1.0.0.6, and XS724EM before 1.0.0.6.
How severe is CVE-2018-21121?: CVE-2018-21121 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-2018-21121 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-21121?: CVE-2018-21121 primarily affects Netgear Gs810emx Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-21121?: 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-2018-21121 published?: CVE-2018-21121 was published on 2020-04-22 and last updated on 2026-06-17.

References

https://kb.netgear.com/000060237/Security-Advisory-for-Authentication-Bypass-on-Some-Switches-PSV-2018-0219

Affected products (3)

cpe:2.3:o:netgear:gs810emx_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:xs512em_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:xs724em_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Netgear Gs810emx Firmware

CVE-2020-26921 — High (CVSS 8.3): Certain NETGEAR devices are affected by authentication bypass. This affects GS110EMX before 1.0.1.7, GS810EMX before…
CVE-2018-21122 — Medium (CVSS 6.5): Certain NETGEAR devices are affected by denial of service. This affects GS110EMX before 1.0.0.9, GS810EMX before…
CVE-2018-21143 — Medium (CVSS 6.5): NETGEAR GS810EMX devices before 1.0.0.5 are affected by disclosure of sensitive information.
CVE-2019-20658 — Medium (CVSS 6.5): Certain NETGEAR devices are affected by disclosure of sensitive information. This affects FS728TLP before 1.0.1.26,…
CVE-2019-20676 — Medium (CVSS 6.0): Certain NETGEAR devices are affected by lack of access control at the function level. This affects FS728TLP before…

All CVEs affecting Netgear Gs810emx Firmware →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →