How severe is CVE-2021-45623?

CVE-2021-45623 has a CVSS 3.x base score of 8.3, 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 low.

Is CVE-2021-45623 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-45623?

CVE-2021-45623 primarily affects Netgear R7800 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-2021-45623?

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-2021-45623 published?

CVE-2021-45623 was published on 2021-12-26 and last updated on 2026-06-17.

CVE-2021-45623

CVE-2021-45623 is a high-severity vulnerability in Netgear R7800 Firmware with a CVSS 3.x base score of 8.3. 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-77.

Key facts

Severity: High (CVSS 3.x base score 8.3)
CVSS v2: 7.5
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-77
Affected product: Netgear R7800 Firmware
Published: 2021-12-26
Last modified: 2026-06-17

Description

Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects R7800 before 1.0.2.74, R9000 before 1.0.5.2, and XR500 before 2.3.2.66.

Frequently asked questions

What is CVE-2021-45623?: Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects R7800 before 1.0.2.74, R9000 before 1.0.5.2, and XR500 before 2.3.2.66.
How severe is CVE-2021-45623?: CVE-2021-45623 has a CVSS 3.x base score of 8.3, 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 low.
Is CVE-2021-45623 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-45623?: CVE-2021-45623 primarily affects Netgear R7800 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-2021-45623?: 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-2021-45623 published?: CVE-2021-45623 was published on 2021-12-26 and last updated on 2026-06-17.

References

https://kb.netgear.com/000064449/Security-Advisory-for-Pre-Authentication-Command-Injection-on-Some-Routers-PSV-2019-0203

Affected products (3)

cpe:2.3:o:netgear:r7800_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:r9000_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:netgear:xr500_firmware:*:*:*:*:*:*:*:*

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