Is CVE-2025-20239 actively exploited?

No active exploitation of CVE-2025-20239 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2025-20239 be exploited remotely?

Yes. CVE-2025-20239 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2025-20239?

CVE-2025-20239 has a CVSS score of 8.6 (HIGH).

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HIGH

CVE-2025-20239

CWE-401Published: August 14, 2025· Updated: Jun 17, 2026

8.6

CVSS v3.1

Official Description

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) feature of Cisco IOS Software, IOS XE Software, Secure Firewall Adaptive Security Appliance (ASA) Software, and Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a memory leak, resulting in a denial of service (DoS) condition.

This vulnerability is due to a lack of proper processing of IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device. In the case of Cisco IOS and IOS XE Software, a successful exploit could allow the attacker to cause the device to reload unexpectedly. In the case of Cisco ASA and FTD Software, a successful exploit could allow the attacker to partially exhaust system memory, causing system instability such as being unable to establish new IKEv2 VPN sessions. A manual reboot of the device is required to recover from this condition.

NVD Source

Technical Analysis

CVE-2025-20239 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 8.6.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.