CVE-2021-21728

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-04-09 · updated 2026-06-17
Weakness: CWE-400

Description

A ZTE product has a configuration error vulnerability. Because a certain port is open by default, an attacker can consume system processing resources by flushing a large number of packets to the port, and successfully exploiting this vulnerability could reduce system processing capabilities. This affects: ZXA10 C300M all versions up to V4.3P8.

Affected products

ZXA10 C300M: before 4.5 — fixed in 4.5

How to fix

Upgrade to a fixed version: ZXA10 C300M 4.5. Check the vendor advisory for mitigations.

References

https://support.zte.com.cn/support/news/LoopholeInfoDetail.aspx?newsId=1014784
https://support.zte.com.cn/support/news/LoopholeInfoDetail.aspx?newsId=1014784

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