KZ Broadband JT3500V session expiration

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.3$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in KZ Broadband JT3500V, AM6200M, AM6000N, AM5000W, AM4200M, AM4100V, AM3500MW, AM3410V, AM3300V, AM3100E, AM3100V, AM3000M, KZ7621U, KZ3220M and KZ3120R. Affected by this vulnerability is an unknown functionality. Executing a manipulation can lead to session expiration. This vulnerability is tracked as CVE-2021-47740. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in KZ Broadband JT3500V, AM6200M, AM6000N, AM5000W, AM4200M, AM4100V, AM3500MW, AM3410V, AM3300V, AM3100E, AM3100V, AM3000M, KZ7621U, KZ3220M and KZ3120R. It has been declared as critical. This vulnerability affects an unknown function. The manipulation with an unknown input leads to a session expiration vulnerability. The CWE definition for the vulnerability is CWE-613. According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization." As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The weakness was disclosed by Gjoko Krstic as ZSL-2021-5646. The advisory is available at zeroscience.mk. This vulnerability was named CVE-2021-47740 since 12/23/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 12/31/2025).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

Name

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.4
VulDB Meta Temp Score: 7.3

VulDB Base Score: 7.3
VulDB Temp Score: 7.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Session expiration
CWE: CWE-613
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

12/23/2025 CVE reserved
12/31/2025 +8 days Advisory disclosed
12/31/2025 +0 days VulDB entry created
12/31/2025 +0 days VulDB entry last update

Sourcesinfo

Advisory: ZSL-2021-5646
Researcher: Gjoko Krstic
Status: Not defined

CVE: CVE-2021-47740 (🔒)
GCVE (CVE): GCVE-0-2021-47740
GCVE (VulDB): GCVE-100-339262

Entryinfo

Created: 12/31/2025 20:15
Changes: 12/31/2025 20:15 (73)
Complete: 🔍
Cache ID: 216::103

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