Cyber Resilience

CVE-2021-47740

MediumPublic PoC

Published: 31 December 2025

Published
31 December 2025
Modified
15 April 2026
KEV Added
Patch
CVSS Score v4 6.9 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0010 27.3th percentile
Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-47740 is a medium-severity Insufficient Session Expiration (CWE-613) vulnerability in Kzbtech (inferred from references). Its CVSS base score is 6.9 (Medium).

Operationally, ranked at the 27.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

Kzbtech
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-613

Locks the device (typically after inactivity) until re-authentication, addressing insufficient session expiration by preventing indefinite access.

addresses: CWE-613

Automatically terminating sessions after a defined period directly enforces session expiration, preventing indefinite session lifetimes that attackers can exploit.

addresses: CWE-613

Re-authentication after inactivity or time-based triggers prevents indefinite use of potentially hijacked or stale sessions.

addresses: CWE-613

Terminating sessions and network connections upon completion prevents insufficient session expiration.

addresses: CWE-613

Directly enforces termination of network sessions after inactivity or end-of-session, preventing indefinite session lifetime.

addresses: CWE-613

Consistent clocks across systems allow session expiration and timeout enforcement to function as intended in distributed environments.

addresses: CWE-613

When the non-persistent artifact is a session or connection, mandatory termination implements the missing expiration that CWE-613 describes.

addresses: CWE-613

Timed refresh of session-related information or on-demand generation plus deletion implements proper session expiration.

References