How severe is CVE-2021-47740?

CVE-2021-47740 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-47740 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2021-47740?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2021-47740 have an EU (EUVD) identifier?

Yes. CVE-2021-47740 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206077.

When was CVE-2021-47740 published?

CVE-2021-47740 was published on 2025-12-31 and last updated on 2026-06-17.

CVE-2021-47740

CVE-2021-47740 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-613.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 6.9
EPSS exploit prediction: 0% (30th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-206077
Weakness: CWE-613
Published: 2025-12-31
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-47740?: 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.
How severe is CVE-2021-47740?: CVE-2021-47740 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-47740 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2021-47740?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2021-47740 have an EU (EUVD) identifier?: Yes. CVE-2021-47740 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206077.
When was CVE-2021-47740 published?: CVE-2021-47740 was published on 2025-12-31 and last updated on 2026-06-17.

References

Other CWE-613 (Insufficient Session Expiration) vulnerabilities

CVE-2024-8888 — Critical (CVSS 10.0): An attacker with access to the network where CIRCUTOR Q-SMT is located in its firmware version 1.0.4, could steal the…
CVE-2026-46455 — Critical (CVSS 9.8): Insufficient Session Expiration vulnerability in Apache Camel Keycloak Component. The camel-keycloak security helper…
CVE-2026-21622 — Critical (CVSS 9.8): Insufficient Session Expiration vulnerability in hexpm hexpm/hexpm ('Elixir.Hexpm.Accounts.PasswordReset' module)…
CVE-2025-59786 — Critical (CVSS 9.8): 2N Access Commander version 3.4.2 and prior improperly invalidates session tokens, allowing multiple session cookies to…
CVE-2026-26342 — Critical (CVSS 9.8): Tattile Smart+, Vega, and Basic device families firmware versions 1.181.5 and prior implement an authentication token…
CVE-2026-1435 — Critical (CVSS 9.8): Not properly invalidated session vulnerability in Graylog Web Interface, version 2.2.3, due to incorrect management of…

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