Is CVE-2021-21727 in the CISA KEV catalog?

No. CVE-2021-21727 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-21727?

CVE-2021-21727 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2021-21727?

CVE-2021-21727 has an EPSS score of 1.39% (69th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-21727?

Upgrade zxhn f623 firmware to 6.0.0p3t34 or later.

CVE & CISA-KEV Catalog

CVE-2021-21727

HIGH

7.5

CVSS v3

NVD

Description

A ZTE product has a DoS vulnerability. A remote attacker can amplify traffic by sending carefully constructed IPv6 packets to the affected devices, which eventually leads to device denial of service. This affects:<ZXHN F623><All versions up to V6.0.0P3T33>

How to fix

Remediation Available

zxhn f623 firmwareNVD

Affected:< 6.0.0p3t34Fixed in:6.0.0p3t34CVE-2021-21727derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

1.39%probability of exploitation in 30 days

69thpercentile

Moderate risk: more likely to be exploited than 69% of all known CVEs.

References

Vendor Advisory1

support.zte.com.cn

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.