CVE-2025-20239
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 De
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.
Weakness: CWE-401
Affected products
| Vendor | Product | Category | Matched by |
|---|---|---|---|
| Cisco | Cisco Adaptive Security Appliance (ASA) Check your version | Firewall / NGFW | cna-assigner |
| Cisco | Cisco Firepower Threat Defense (FTD) Check your version | Firewall / NGFW | cna-assigner |
| Cisco | Cisco IOS Software | Routing & Switching | cna-assigner |
| Cisco | Cisco IOS XE Software | Routing & Switching | cna-assigner |
Vendor-reported products (4)
- Cisco · IOS
- Cisco · Cisco Adaptive Security Appliance (ASA) Software
- Cisco · Cisco IOS XE Software
- Cisco · Cisco Firepower Threat Defense Software
Vendor advisory
cisco-sa-asa-ftd-ios-dos-DOESHWHy
Cisco IOS, IOS XE, Secure Firewall Adaptive Security Appliance, and Secure Firewall Threat Defense Software IKEv2 Denial of Service Vulnerabilities
Cisco’s rating: High (advisory CVSS 8.6) · Published Aug 14, 2025
Bug IDs: CSCwn73399 , CSCwn83263 , CSCwo15021 , CSCwo15022 , CSCwo15023 , CSCwo15024 , CSCwo15026 , CSCwo20388 , CSCwo49928 , CSCwo49948
The vendor’s rating applies to the whole advisory and can differ from this CVE’s own CVSS severity. Where this comes from